Answer:
a) Solving by factoring, you move 225 to the left side by subtracting then making the equation equal to 0.
b) x = -15
x = 15
Explanation:
1. x^2 -225=0
2. Find what two numbers equal to -225 then factor by using the expression a^-b^2=(a-b)(a+b)
In this case, -15(15)=-225
(x-15)(x+15)=0
3. Find x
x-15=0
x+15=0
This equation has 2 solutions
x=-15
x=15
To check answer, one of the solutions into X