diketahui fungsi f adalah f(x) = px +q. Jika f(-4)=-26 dan f (3)=16, maka nilai p + q adalah

Jawab :

f(x) = px + q
f(-4) = p(-4) + q = -4p + q = -26
f(3) = p(3) + q = 3p + q = 16

-4p + q = -26
3p + q = 16
_____________ -
-7p = -42
p = 6

3p + q = 16
3(6) + q = 16
18 + q = 16
q = 16 - 18
q = -2

Nilai P + Q = 6 - 2 = 4

f(x) = px + q
f(-4) = p(-4) + q = -26
f(3) = p (3) + q = 16

Eliminasi
f(3) = 3p + q = 16
f(-4) = -4p + q = -26
------------------------------ dikurangi
7p = 42
p = 42/7
p = 6

Subsitusi
f(3) = 3p + q = 16
3(6) + q = 16
18 + q = 16
q = 16 - 18
q = -2

Nilai p + q = 6 + (-2) = 4