Question

the solution set of x2 + 10x + 21 = 0 is

Answer 1

x2+10x+21=0
x2+(7x+3x)+21=0
x2+7x+3x+21=0
x(x+7)+3(x+7)=0
(x+3)(x+7)=0
x+7=0. x+3=0
x=-7. x=-3

Answer 2

2x+10x+21=0
12x=-21
x=-21/12
x=-1.75
This is ur answer.