diketahui rumus suatu fungsi f(x) = ax + b, f(3) = 5, dan f(-1) = -3 tentukan : a. nilai a dan b b. rumus fungsi f(x) c. maka nilai f(4) adalah...

Kelas 8 Matematika
Bab Fungsi

a] f(x) = ax + b

f( 3 ) = 3a + b = 5
f(-1) = -a + b = -3
-------------------------- -
4a = 8
a = 8/4
a = 2

3a + b = 5
3 . 2 + b = 5
b = 5 - 6
b = -1

b] f(x) = 2x - 1

c] f(4) = 2 . 4 - 1
f(4) = 8 - 1
f(4) = 7