Question

What is x(x-7)=30

Answer 1

simplify first,
x(x-7)=30
x^2 - 7x = 30
x^2 - 7x - 30 = 0
then factorize it, get
(x - 10)(x + 3) = 0

now set up each factor be zero, then solve for x
x - 10 = 0
x = .... ?

x+3 = 0
x = .... ?

there are 2 possible x's there