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Find the values of p and q such that (x - 1)and (x - 3) a...

Find the values of p and q such that (x - 1)and (x - 3) are factors of px3 + qx2 + 11x - 6

A.

-1, -6

B.

1, -6

C.

1, 6

D.

6, -1

Correct answer is B

Since (x - 1), is a factor, when the polynomial is divided by (x - 1), the remainder = zero

\therefore (x - 1) = 0

x = 1

Substitute in the polynomial the value x = 1

= p(1)^3 + q(1)^2 + 11(1) - 6 = 0

p + q + 5 = 0 .....(i)

Also since x - 3 is a factor, \therefore x - 3 = 0

x = 3

Substitute p(3)^3 + q(3)^2 + 11(3) - 6 = 0

27p + 9q = -27 ......(2)

Combine eqns. (i) and (ii)

Multiply equation (i) by 9 to eliminate q

9p + 9q = -45

Subtract (ii) from (i), 18p = 18

\therefore p = 1

Put p = 1 in (i), 

1 + q = -5 \implies q = -6

(p, q) = (1, -6)