Question

If x+a is a common factor of f(x) = x² + x-6 and g(x) =x² +3x -18 then find the value of a.

Answer 1

let (x+a) =0

then x= -a

put x=-a in f(x)

x^{2}+x-6=(-a)2-a-6=0

a2-3a+2a-6=0

a(a-3)+2(a-3)=0

(a-3)(a+2)=0

a=3,-2

now put x=-a in g(x)

x2+3x-18=(-a)2+3(-a)-18=0

a2-3a-18=0

a2-6a+3a-18=0

a(a-6)+3(a-6)=0

(a-6)(a+3)=0

a=6,-3

Answer 2

Answer:

same as above please follow