funsi f (x) = ax+b, jika f (2) = -2 dan f (-3) = 13 maka nilai f (4) adalah

langsung aja y

f(2) = 2x + b = -2
f(-3) = -3x + b = 13
_____________-
5x = -15
x = -3

2x + b = -2
b = -2 - 2(-3)
b = -2 + 6
b = 4

f(x) = ax + b
f(x) = -3x + 4

f(4) = -3(4) + 4
f(4) = -12 + 4
f(4) = -8

semoga berguna +_+

f (x) = ax + b

f (2) = -2
2a + b = -2....... (pers.1)

f (-3) = 13
-3a + b = 13.........(pers.2)

Eliminasi pers1 dan 2
2a + b = -2
-3a + b = 13
_________ _
5a = -15
a = -15/5
a = -3

Substitusi a = -3 ke pers1 atau pers.2
2a + b = -2
2 (-3) + b = -2
-6 + b = -2
b = -2 + 6
b = 4

Rumus f (x) :
f (x) = ax + b
f (x) = -3x + 4

Nilai f (4)
= -3 (4) + 4
= -12 + 4
= -8