Answer:
x=-7,-3
Explanation:
x^2+10x+21
(x+3)(x+7)= 0
x^2+7x+3x+21= x^2+10x+21
x+3-3= 0-3
x+7-7= 0-7
Answers are :
x= -3 , x= -7
5.8m questions
7.5m answers