Answer:
×=-7,×=-3
Step-by-step explanation:
plz don't mind my "×"
×^2+10×+21=0
×^2+7×+3×+21=0
rearrange
that is ; ×^2+3×+7×+21=0
(×^2+3×)+(7×+21)=0
×(×+3)+7 (×+3)=0
therefore
(×+7) (×+3)=0
×+7=0 ×+3=0
×= -7 ×=-3
