Question

What are the solution(s) to the quadratic equation x2 – 25 = 0?

A.x = 5 and x = –5
B.x = 25 and x = –25
C.x = 125 and x = –125
D.no real solution

Answer 1

difference of 2 perfect squares
a^2-b^2=(a-b)(a+b)
25=5^2
x^2-5^2=(x-5)(x+5)=0
set to zero
x-5=0
x=5
x+5=0
x=-5

x=5 or -5

A