Write down the quadratic equation whose roots are x = -7 and x = 1, and the coefficient of x^2 is 1.
Wondering how you got the positive 7 and negative 1
(x + 7) ( x - 1) = 0
x^2 + 7x - 1x - 7 = 0
x^2 + 6x - 7 = 0
Note that if
(x + 7) (x - 1) = 0
Then either x + 7 = 0 which implies that x = -7 makes this true...so this is a root
OR
x - 1 = 0 which implies that x = 1 makes this true.......so this is also a root
