Fungsi f(x) = ax + b. Jika f(1)= -1 dan f (-3)=21. Maka nilai a dan b adalah

Bab Fungsi
Matematika SMP Kelas VIII

f(x) = ax + b

f(1)  =    a + b = -1
f(-3) = -3a + b = 21
         ------------------- -
                 4a = -22
                   a = -22/4
                   a = -11/2

a + b = -1
-11/2 + b = -1
b = 11/2 - 2/2
b = 9/2

jadi, a = -11/2 dan b = 9/2

f(x) = ax+b
• a + b = -1
• -3a + b = 21
-3a + b = 21
a + b = -1
-------------------- -
-4a = 22
a = 22/-4
a = -5 1/2

-5 1/2 + b = -1
b = -1 - (-5 1/2)
b = 4 1/2