Question

Dadas as funçoes  f(x)= 5x+10  e  g(x)= 4x-3  determine:

a) f o g (x)

b) g o f (x)

c) f o f (x)

Answer 1

$f(x)=5x+10$

$g(x)=4x-3$

a) $f~\text{o}~g(x)$

$f[g(x)]=f(4x-3)=5(4x-3)+10=20x-15+10=20x-5$

b) $g~\text{o}~f$

$g[f(x)]=g(5x+10)=4(5x+10)-3=20x+40-3=20x+37$

c) $f~\text{o}~f$

$f[f(x)]=f(5x+10)=5x(5x+10)+10=25x^2+50x+10$