Question

In a polynomial P(x)=2x³-7x²+kx+20. It P(2)=P(3).
a) find the value of k. then write polynomial
b) then find P(-2)​

Answer 1

Answer:

k= -3

p(-2)= -18

Step-by-step explanation:

P(2)= 2*2^3 - 7*2^2 + k*2 +20

= 16-28+2k+20

= 8+2k

P(3) = 2*3^3 -7*3^2 + k*3 +20

= 54 - 63 +3k +20 = 11+3k

According to question,

11+3k = 8+2k

or, 3k -2k = 8-11

or, k= -3

P(-2) = 2*(-2)^3 -7*(-2)^2 -3*(-2) +20

= -16 -28+6+20

= - 18