Answer:
3) third option
4) second option
a=-8 b=2
Step-by-step explanation:
x^2+6x-16
x^2+(8-2)x-16=0
x^2+8x-2x-16=0
X(X+8)-2(X+8)=0
(X+8)(x-2)=0
Compare with (X+a)(X+b)
Where we get a=-8 b=2