Question

if ( x - 2 ) is one factor of x^2 - ax - 6 =0 and x^2 - 9x+b =0 , then the value pf a + b is
(1) 10
(2) 11
(3) 15
(4) 14
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Answer 1

Answer:

If (x-2) is a factor of x^2+ax-6, We know we have to have x(x-2) which would make it x^2–2x and then because of the -6 we need 3 of them. So that’s x^2+x-6 which is (x-2)(x+3) and a=1

If x-2 is a factor of x^2–9x+b, we know there’s again x^2–2x which leaves us with -7x+b and that means we have -7 to make it right. So that means b is 14.

Sorry if this is confusing, but we have 1+14 or 15