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# algebraic expressions? REAL ANSWERS ONLY PLEASE!!!!!?

if you could give me a few examples , it would be helpful. my sister dosn't understand the math atall!

THANK YOU

### 4 Answers

- 9 years agoFavorite Answer
A combination of constants and variables constitute algebraic expression such as y=ax+b. x and y are variables here while a and b are constants. The variables and the constants can be connected by any operations such as +,-,x or /.

- John AdriaanLv 69 years ago
Here's a simple one:

Harry and Fred are brothers. Harry is twice as old as Fred. Together, their ages add up to 24. How old are Harry and Fred?

At the beginning, you don't know how old either brother is. One way to solve this is to give each brother a different letter to represent their age. Let H be how old Harry is, and F be how old Fred is.

Now you can write down some algebraic expressions about their ages.

First, they add up to 24:

H + F = 24

Second, Harry is twice as old as Fred, so Harry is two times older than Fred

H = 2F

(When there's no symbol between the number and the letter, it means "times")

Now, this is important. See the equals signs? That means that the left and right hand sides are exactly the same. In other words, where you have the left hand side, you can instead use the right hand side.

So if H = 2F, then you can substitute for H in the first equation H+F=24:

2F + F = 24

OK. Now you've got two Fs, and you're adding one more F. That's three F's, right?

3F = 24

That means that three Fs are 24, which means that one F is 24÷3 = 8. (Note that / is another symbol for ÷)

A quick detour. Do you agree that 3=3? Pretty obvious, right? What happens if you add the same number to both sides of this equation? 3+2=3+2? 5=5? That's still true, isn't it? Now what happens if you multiply both sides of the equation by the same number? 5x3 = 5x3? 15=15? That's still true, isn't it? And if you divide both sides by the same number? 15/5 = 15/5? 3=3? Still true! In other words, if you have an equation, you can do the same "thing" to both sides of the equation and it remains true.

Back to the problem: if 3F=24, then we can divide both sides of the equation by 3:

3F/3 = 24/3

F = 8

That means that Fred = 8. And we know that Harry is twice Fred's age, so Harry must be 8x2=16.

Quick check: do both their ages add up to 24? Does 8+16=24? Yes! We must be right!

Fred is 8 years old, and Harry is 16 years old.

- 9 years ago
5x+7=17 is an example

The following are some helpful sites.

Source(s): http://www.themathpage.com/alg/algebraic-expressio... http://www.mathgoodies.com/lessons/vol7/equations.... - Anonymous9 years ago
Do you mean like this: 2(x-4)*(6-3x)

or

Like this: 2x-4=34