Question

4. x^2+13x=-42
a. x = -6 or x = -7
b. x = 42/13 or x = 0
c. x = 6 or x = 7
d. x = 0 or x = 2

Answer 1

$x^2+13x=-42\ \ \ |+42\\\\x^2+13x+42=0\\\\x^2+6x+7x+42=0\\\\x(x+6)+7(x+6)=0\\\\(x+6)(x+7)=0\iff x+6=0\ \vee\ x+7=0\\\\x=-6\ \vee\ x=-7$

Anaswer: a. x = -6 or x = -7