Question

if X + a is a common factor of f(x)=X^2 + X - 6 and g(x)=X^2 + 3x-18 then find the value of a.​

Answer 1

Answer:

x+a=0

x=-a

f(x)=(-a)^2+(-a)-6

=a^2-a-6

g(x)=a^2-3a-18

then,

f(x)-g(x)=0

-4a-24=o

4a=-24

a=-6

Answer 2

Step-by-step explanation:

x + a is factor of f(x)=X^2 + X - 6

X^2 + X - 6 = 0

(-a)^2 -a -6 =0 ........ (i)

and also the factor of g(x)=X^2 + 3x-18

(-a)^2 -3a - 18 = 0........ ii

equating both

a^2 -a -6 = a^2 -3a -18

3a - a = -12

2a = -12

a = -6