Q2 of 31 Page 239

Find a second degree polynomial p(x) such that p(1) = 0 and p(–2) = 0.

Given, p(1) = 0, p(– 2) = 0


Need to find a polynomial p(x) of second degree


since we know that p(1) = 0


if x = 1 is substituted in p(x) then it satisfies the equation


x – 1 = 0 , and x – 1 is one factor of p(x)


And p(– 2) = 0 is given


if x = – 2 is substituted in p(x) then it satisfies the equation


x + 2 = 0, and x + 2 is one factor of p(x)


since, x – 1 and x + 2 are the factors of p(x), it can be written as follows


p(x) = (x – 1)(x + 2)


p(x) = x2 – x + 2x – 2


p(x) = x2 + x – 2


x2 + x – 2 is the second degree polynomial which satisfies p(1) = 0 and p(– 2) = 0.


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