Suatu fungsi ditentukan oleh rumus f(x) = a + bx. jika f(2) =( -3 )dan f(-1) =( -2), nilai f(-2) adalah...

f(x) = a + bx
f(2) = (-3)
→ (-3) = a + b(2)
(-3) = a + 2b

f(-1) = (-2)
→ (-2) = a + b(-1)
(-2) = a - b

Eliminasi:
a + 2b = -3
a - b = -2
――――――――― (-)
3b = -1
b = -1/3

Ambil salah satu persamaan tadi:
a - b = -2
a - (-1/3) = -2
a + 1/3 = -2
a = -2 - 1/3
a = -6/3 - 1/3
a = -7/3

Sekarang, hitung f(-2):
f(-2) = a + bx
f(-2) = -7/3 + [(-1/3) x (-2)]
f(-2) = -7/3 + 2/3
f(-2) = -5/3