Question

If x-3 is a factor of x2-ax-15, then a =

Answer 1

Answer:

hey mate here is your answer

x-3=3

x2-ax-15

(3)2-a(3)-15

9-3a-15

-6-3a

3a=6

a=2

Answer 2

Let -3 +b be a

Using identity:-

(x+a)(x+b)=x^2+(a+b)x+ab

(x-3)(x+b)=x^2-ax-15

-3b=-15

b=5

a= -3+b=>-3+5=>2

:.a=2

Hope it helps you.

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