Respuesta :

remember
a^2-b^2=(a-b)(a+b)

first factor out 5
5(x^2-25)=0
or
5(x^2-5^2)=0
5(x-5)(x+5)=0
set to zero
x-5=0
x=5
x+5=0
x=-5

x=-5 and 5
5x^2 - 125 = 0
5x^2 = 125
x^2 = 125/5
x^2 = 25
x = 5, -5

hope this help