Question

15) Dada a função f (x)= 8x +15,calcule:
b) f (5) - f (10)
c) f (7) + f (- 3)
d) f (2) + f (3)

Answer 1

b) f(5) - f(10)

$f(x)= 8x +15 \\ \\ f(5) = 8 \cdot 5 +15 \\ \\ f(5) = 40+15 \\ \\ f(5)=55$


$f(x)= 8x +15 \\ \\ f(10) = 8 \cdot 10 +15 \\ \\ f(10) = 80+15 \\ \\ f(10)=95$


$f(5) - f(10) = 55-95 = -40$


c) f(7) + f(- 3)

$f(x)= 8x +15 \\ \\ f(7) = 8 \cdot 7 +15 \\ \\ f(7) = 56+15 \\ \\ f(7)=71$


$f(x)= 8x +15 \\ \\ f(-3) = 8 \cdot (-3) +15 \\ \\ f(-3) = -24+15 \\ \\ f(-3)=-9$


$f(7) + f(- 3) = 71+(-9)=71-9=62$


d)  f(2) + f(3)

$f(x)= 8x +15 \\ \\ f(2) = 8 \cdot 2 +15 \\ \\ f(2) = 16+15 \\ \\ f(2)=31$


$f(x)= 8x +15 \\ \\ f(3) = 8 \cdot 3 +15 \\ \\ f(3) = 24+15 \\ \\ f(3)=39$


$f(2) + f(3) = 31+39 = 70$


Bons estudos!