(a+12)(a-4)
You have to find the sum of 8 that is also the product of -48

armmermom2x

a^2+8a-48=0
First factor it
(a+12)(a-4)=0
a=-12 or a=4
Then lets substitute
1)a=-12
a^2+8a-48=0
(-12)^2+8(-12)-48=0
144-96-48=0
0=0
2)a=4
a^2+8a-48=0
4^2+8(4)-48=0
16+32-48=0
0=0
Therefore both answers can be used in both equations