# Simplifying and expanding expressions

• MHB
litchris
I have a test on simplifying and expanding expressions, could someone help me with this. I don't understand the formula and the way you do it

skeeter
Do you have specific examples of expressions requiring expansion and/or simplification?

Post a few you have attempted, showing how you tried them yourself ... help us help you.

litchris
i tried 4x+7x-5x and 4x^2-2xy-3y^2+6xy+3y^2-x^2 totally confused.

skeeter
you can sum like terms ...

4x, 7x and -5x are all like terms $\implies 4x + 7x - 5x = 11x - 5x = 6x$

for the second, like terms have the same variables to the same power. like terms have the same color in the expression below ...

${\color{red}4x^2} {\color{blue}-2xy} {\color{green}-3y^2}{\color{blue}+6xy}{\color{green}+3y^2}{\color{red}-x^2}$

I assume you know how to sum terms with the same and/or different signs
Why don't you try and combine them ...

have a look at the link, too
https://www.mathsisfun.com/algebra/like-terms.html

Last edited by a moderator:
litchris
Thanks skeeter this helps

SDAlgebra
Would you use brackets in your test? In that case...

You multiply each number in the brackets by the other brackets for example: [ (x+y)(x+y) ] would equal [ x2 + xy + xy + y2 ]. Simplifying these expressions would equal x2 + 2xy + y2

Or...

As Skeeter said you combine the expressions from different sides to make a final answer.

4x+7y+2x+9y = 6x + 16y

These are purposely easier just for you to get the gist :)