Question

Solve this null factor law question

10x^2-40x-210=0

Answer 1

10x²-40x-210 =0

we simplify by 10 before doing the calculations it will be simpler

x²-4x-21=0

a=1 b=-4 c=-21

b²-4ac = (-4)²-4(1*-21)= 16+84=100

Δ =100;

(-b-√Δ)/2a =(4-10)/2=-6/2=-3

(-b+√Δ)/2a =(4+10)/2 = 7

S{-3;7}