fungsi h(x)=ax+b. jika h(3)=-4 dan h(4)=-7, nilai h(-1) adalah

h(x) = ax + b
h(3) = -4
-4 = a.3 + b
3a + b = -4
b = -4 - 3a
h(4) = -7
-7 = a.4 + b
4a + b = -7
4a - 4 - 3a = -7
a = -7 + 4
a = -3
b = -4 -3(-3)
b = -4 + 9
b = 5
h(x) = -3x + 5
h(-1) = -3(-1) + 5
h(-1) = 3 + 5
h(-1) = 8

Bab Fungsi
Matematika SMP kelas VIII

h(x) = ax + b

h(3) = 3a + b = -4
h(4) = 4a + b = -7
        ----------------- -
                 -a = 3
                  a = -3

3a + b = -4
3 . (-3) + b = -4
b = 9 - 4
b = 5

h(x) = -3x + 5

h(-1) = -3 . (-1) + 5
        = 3 + 5
        = 8