Question

considere a função f(x)=3x²+x-1 e g(x)=2x+5. Determine

a)f(g(x))

Answer 1

$f(x)=3 x^{2} +x-1$

$g(x)=2x+5$

$f(g(x))=f(2x+5)=3 .(2x+5)^{2} +(2x+5)-1$$=3.(4 x^{2}+20x+25)+2x+4=12 x^{2} +60x+75+2x+4$$=12 x^{2} +62x+79$