# Algebra Feedback

by Ron Kurtus

Readers have sent in a total of 66 comments and questions on Algebra issues. They are listed according to date.

## List of next 15 letters

### Country

Solve this problem General Ghana

Spending money problem General Ghana

Solve problem General Ghana

Need help to understand basic Algebra General USA

Why are letters used in algebra? Terminology USA

Do you have DVDs of courses? General Somalia

Correcting error in test General USA

Solve my homework General India

Multiplication problem Multiplying Binomial Expressions Philippines

Following the laws for exponents Variables and Constants U.A.E.

I need help to understand the term sub-expression Expressions USA

Two exceptions in equations Linear Equation with One Variable USA

How do you do 4 to the negative 5 power? Division with Exponents USA

Tough algebra problems Linear Equation with One Variable India

Next 15 letters

First 15 letters

## Solve this problem

March 25, 2011

### Question

solve

3^2x+1_28(3^x-1)=0

I'm sorry, but we do not solve homework problems.

## Spending money problem

March 16, 2011

### Question

A Girl spent 3/5 of her pocket money and was left with 1,800. How much must be her pocket money.

Look in our section on Algebra to learn how to do such problems.

She was left with 1 - 3/5 = 2/5 of her money.
If M is her original money, then 2/5 x M = 1800
Her pocket money was 4500.

## Solve problem

February 18, 2011

### Question

SOLVE: 3X^3+2X-10=0

Sorry, there is no easy solution for that problem. It is beyond our scope.

## Need help to understand basic Algebra

February 10, 2011

### Question

I am 65 years old and i need some help on understanding the basic algebra easy things to remember since i have never taken algebra before. I am going to college and i have to have this course. i hope you can help an old lady.

linda - USA (21177)

Feel free to go through our Algebra lessons. They will give you a good background to help you understand the subject. Also, look at some of our resources. Some include practice exercises.

Algebra can be complex, so try to be methodical and do one step at a time. It is better to write down each step instead of trying to do things in your head, as some teachers demonstrate.

Best wishes doing well in school.

## Why are letters used in algebra?

January 21, 2011

### Question

I still say that no letters or something is not valid in Algebra. All it does is confuse you.It is not easier.So,do letters take place of numbers? How do you add and subtract letters. Why put more letters in Algebra? Leave 1+1=2 alone. Do this need letters? To much figuring.

- USA (21050)

A letter in an Algebra expression or equation represents something that does not have a number assigned to it yet. It is an unknown quantity. You could use the name of something instead of a letter. For example: 3 apples + 5 apples = ?? But it is easier to write this as 3a + 5a + ?? Then the equation will also work if a = bananas or something else.

You do not have to use letters. You can use symbols, such as a smiley face if you want, as long as you are consistent. However, the teachers may not like using a smiley face.

I hope that helps.

## Do you have DVDs of courses?

January 13, 2011

### Question

do you have any course DVDs of mathmatical and science for high school students or other websites which can help for our how we study them as international? thanks you

hassan - Somalia (21015)

I'm sorry, but we do not have any DVDs on our courses at this time. Your high school students can go through our lessons to help them learn the subjects. Also, each lesson and each subject has a list of resources. For example, a list of other Algebra websites can be seen at:

http://www.school-for-champions.com/algebra/resources.htm

## Correcting error in test

November 29, 2010

### Question

I noticed an error in your first Algebra test on question 15. The expression listed does not match any of the choices offered. It would seem that the x was placed on the wrong side of the parenthesis.

(excerpt from test)
15. Which of the following is equal to -7x(3 - 2y - z)?

Not Sure

-21x - 14y - 7z

21x + 14y - 7z

-21x + 14y + 7z
(end inclusion)

Brian - USA (20759)

Thanks for letting me know about it. I corrected the error. It should have been -7(3x - 2y - z)

You might have to refresh the page to verify the question has been updated.

Thanks, again.

## Solve my homework

November 16, 2010

### Question

1) prove by mean value theorm 3+(1/28)<(28)^(1/3)<3+(1/27).
^ means the power of (28) is 1/3.

2)prove that x-1<1/10 then x^3+1<0.331.
x-1 means in mode x-1.

3)prove by sandwich theorm for sequence that as n tends to infinite x^n=0 and x<1 is given.
please send me the solutions as soon as possible.

rrg - India (20705)

I'm sorry, but we cannot solve homework problems.

## Multiplication problem

June 30, 2010

### Question

multiply: [125(a+b)^25][-25(a+b)^20]

Wylbur - Philippines (19987)

Since the expressions are all multiplied together, they really are not binomial expressions.

Simply multiply:

(125)*(-25) = -3125

[(a+b)^25]*[9a+b)^20] = (a+b)^45

So, the answer is: -3125(a+b)^45. You are not expected to put (a+b)^45 in any other form.

## Following the laws for exponents

June 8, 2010

### Question

greetings!! I am a grade 6 student studying in the U.A.E. I really want to know algebra more since our school here is so advanced. i just want to ask,,, in algebra, is there a need for the laws of exponents. i mean should we follow the rules??? and please teach me how to solve different kinds of long equations because it is kind of confusing.
I usually fail in math because of problem solvings....

Thanks!!!!

Hannah Grace - U.A.E. (19861)

There are definite laws or rules for multiplying and dividing exponents. It is good to know those rules, because it makes the activities easier. Otherwise you need to break down the exponent as repeated multiplications, and that can really slow you down.

For the rules, see:
http://www.school-for-champions.com/algebra/exponents_multiplication.htm
and
http://www.school-for-champions.com/algebra/exponents_division.htm

Best wishes for top grades in algebra.

## I need help to understand the term sub-expression

February 4, 2010

### Question

I need help to understand the term sub-expression. I had never seen that until I came to your web site. I like the immediate interaction questions because it helps me to understand the concepts when I know if my answer is right or not. I found out that you have to be in a peaceful state of mind and have a clear head in order to study algebra. It is not possible to understand it when you have other personal issues going on in your brain.

Ms. M. - USA (19158)

If you have a complex expression, you can consider parts of it as sub-expressions. For example, the expression 2Y + (3Z + 1) has sub-expressions 2Y and 3Z + 1.

Calling them sub-expressions just allows you to realize that they are expressions within a larger expression. Some Algebra books do not distinguish between expression and sub-expressions.

## Two exceptions in equations

January 6, 2010

### Question

It is said that there are 2 exceptions to the rule; What you do on the left side of the equal sign, you must do on the right side. What are those 2 exceptions?

Luis - USA (18982)

You cannot multiply or divide both sides by zero.

## Explain how the quadratic formula is derived

December 23, 2009

### Question

Ann - USA (18917)

## How do you do 4 to the negative 5 power?

November 19, 2009

### Question

How do you do 4 to the negative 5 power?

- USA (18704)

A number raised to a negative exponent equals the reciprocal of the number raised to a positive exponent. For example, 4^-5 = 1/4^5.

## Tough algebra problems

September 27, 2009

### Question

these are some of my questions i read in class 8th cbse and have to do hard work in this board session so i need some help:-
1.if i add 10 to 4 times anumber, the result is five less than five times the number. what is my number?
2.what are 3 consecutive odd integers.the sum of 1st and last of these integers is 26.what are the integers?
that much some of my queries i'll ask you later as i take time.

Anshul - India (18394)

Add 10 to 4 times a number = 4x + 10
Result is 5 less than 5 time number = 5x - 5
Thus 4x + 10 = 5x - 5
Subtract 4x from both sides and add 5 to both sides of the equation.
15 = x

The second problem is tricky. 2x is always an even number and 2x + 1 is odd.
Let 2x + 1 = first odd integer, 2x + 3 = second, 2x + 5 = third.
(2x + 1) + (2x + 5) = 26
4x + 6 + 26
4x = 20
x = 5
2x + 1 = 11, 2x + 3 = 13, 2x + 5 = 15.

## Misc

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