SOLUTION: Factor Completely: 5a^2 - 125 I can not seem to think of how to do this problem with two numbers, can anyone help me out? Thank you

Algebra ->  Distributive-associative-commutative-properties -> SOLUTION: Factor Completely: 5a^2 - 125 I can not seem to think of how to do this problem with two numbers, can anyone help me out? Thank you      Log On


   

Question 70365: Factor Completely:
5a^2 - 125
I can not seem to think of how to do this problem with two numbers, can anyone help me out? Thank you
Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
Factor Completely:
5a^2 - 125
First factor out the greatest common factor, 5:
5(a^2)-5(25)
5(a^2-25)
Now you have the diffence of two square x%5E2-y%5E2=%28x%2By%29%28x-y%29, your x=a and y=5
highlight%285%28a%2B5%29%28a-5%29%29
To check, multiply it back out to see if you get back to where you started.
5[a(a-5)+5(a-5)]
5[a(a)+a(-5)+5(a)+5(-5)]
5(a^2-5a+5a-25)
5(a^2-25)
5(a^2)+5(-25)
5a^2-125 We're right!!!!
Happy Calculating!!!!