How do you simplify #(x+3)(x-3)+(x+7)(x-3) #?

1 Answer
Aug 28, 2016

Answer:

#2x^2 +4x-30#

Explanation:

#(x+3)(x-3)+(x+7)(x-3) #

One method would be to multiply the brackets out and collect the like terms together.
This seems a long and tedious method - we will end up with 8 terms which need to be simplified.

We can also use a factoring method because there is a common bracket in each term.

#(x+3)color(red)((x-3))+(x+7)color(red)((x-3)) #

#color(red)((x-3))(x+3 +x+7)#

=#color(red)((x-3))(2x+10)#

=#2x^2 +10x-6x-30#

#2x^2 +4x-30#