Question

Dada a função f (x) = 8x + 15, calcule:
a) f(0)
b) f(3)
c) f(-5)
d)f(-2,5)

Answer 1

A)  f(x)=8x+15
f(0)=8.0+15
f(0)=0+15
f(0)=15

B)  f(x)=8x+15
f(3)=8.3+15
f(3)=24+15
f(3)=39

C)  f(x)=8x+15
f(-5)=8.(-5)+15
f(-5)=-40+15
f(-5)=-25

D)  f(x)=8x+15
f(-2,5)=8.(-2,5)+15
f(-2,5)=-20+15
f(-2,5)=-5

Answer 2

Resolução da questão, veja:

Letra ''A'':

$f (x) = 8x + 15~\to~ f(0)\\\\\ f(0) = 8~\cdot~0+ 15\\\\\ f(0) = 0 + 15\\\\\\ \large\boxed{\boxed{\boxed{\boxed{\boxed{\boxed{f(0) = 15.}}}}}}}}}}}}}$

Letra ''B'':

$f (x) = 8x + 15~\to~ f(3)\\\\\ f(3) = 8~\cdot~3+15\\\\\ f(3) = 24 + 15\\\\\\\ \large\boxed{\boxed{\boxed{\boxed{\boxed{\boxed{\boxed{f(3) = 39.}}}}}}}}}}}}}}}}}$

Letra ''C'':

$f (x) = 8x + 15~\to~ f(-5)\\\\\ f(-5) = 8~\cdot~(-5)+15\\\\\ f(-5) = -40 + 15\\\\\\ \large\boxed{\boxed{\boxed{\boxed{\boxed{\boxed{\boxed{\boxed{ f(-5) = -25.}}}}}}}}}}}}}$

Letra ''D'':


$f (x) = 8x + 15~\to~ f(-2,5)\\\\\ f(-2,5) = 8~\cdot~(-2,5)+15\\\\\ f(-2,5) = -20 + 15\\\\\\ \large\boxed{\boxed{\boxed{\boxed{\boxed{\boxed{\boxed{\boxed{f(-2,5) = -5.}}}}}}}}}}}}}}}}}}}$

Espero que te ajude. :).