Question

Sendo 4 a raiz de: p(x)=x³+7x²+kx-8, calcule K

Answer 1

P(4)=4^3+7×4^2+k×4-8
P(4)= 64+(7×16)+k×4-8
P(4)= 64+112+4k-8
-4k=64+112-8
-4k= 168
k= 168/ -4
k= -42