Question

Calcular polinomios - _-
#Dado P(x) = - x3 + 5x2 - 2x +8, calcular P(1) y P(-3).
#Dado P(x) = 2x3 + x2 + ax - 1 *Hallar el valor de a sabiendo que P(2)=21​

Answer 1

P(x) = - x3 + 5x2 - 2x +8,

P(1)= -(1)3+5(1)(2)-2(1)+8

-3+10-2+8= 13

P(-3)=-(-3)3+5(-3)2-2(-3)+8

-9-30+6+8= -25

P(x) = 2x3 + x2 + ax - 1

P(2)=21

P(2)= 2(2)3+2(2)+a(2)-1

21= 12+4+2a -1

6=2a

a=3