Question

Si f(x) = mx + b; f(1/3) = 6 y f(- 6) = 25 , halla f(8) + f(-8)

Answer 1

Respuesta:

f(1/3)=m(1/3)+b

6=m/3+b

6-b=m/3

18-3b=m

f(-6)=m(-6)+b

25=-6(18-3b)+b

25=-108+18b+b

25=-108+19b

133=19b

7=b

18-3(7)=m

18-21=m

-3=m

f(8)=-3(8)+7=-17

f(-8)=-3(-8)+7=31

-17+31=14

Answer 2

Respuesta:

14

Explicación paso a paso:

f(x) = y

y = mx + b

f(1/3) = m(1/3) + b

f(1/3) = 6

6 = 1/3(m) + b

18 = m + 3b ... (1)

--------------------------------------------------------

f(-6) = m(-6) + b

25 = -6m + b

75 = -18m + 3b ... (2)

2 en 1:

-57 = 19m

m = -3

∴ b = 7

Luego:

f(8) + f(-8) = -3(8) + 7 - 3(-8) + 7

⇒  f(8) + f(-8) = -24 + 14 + 24 ⇒ 14