Question

If x2+x-12 divides p(x)=x2+ax2+bx-84 exactly ,find a and b.Already I have asked this question and you sent me the solution also. but i can't understand.Can we do this sum using division algorithm method.Please it is very urgent.

Answer 1

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Answer 2

2x+x-12=0

3x-12=0

3x=12

x=12/3

x=4

So, p(x) = P(4)

P(x) = 2x + 2ax + xb – 84 = 0

P(4) = 2(4) + 2a(4) + (4)b - 84 = 0

        = 8 + 8a + 4b – 84 = 0

        = 8a + 4b – 76 = 0

        = 8a + 4b = 76

        = a + b = 76/8*4

        = a + b = 76/24

        = a + b = 19/6