dikerahui f(x) =px + q, f(-1) =-5 dan f(4)=5. Nilai f(-6) adalah

[tex]f(-1)=-p+q=-5[/tex]
[tex]-p+q=-5[/tex]
[tex]q=p-5[/tex]

[tex]f(4)=4p+q=5[/tex]
[tex]4p+q=5[/tex]
[tex]4p+p-5=5[/tex]
[tex]5p=10[/tex]
[tex]p=2[/tex]
[tex]q=p-5=2-5=-3[/tex]

[tex]f(x)=2x-3[/tex]
[tex]f(-6)=2*(-6)-3=-15[/tex]

# f(x) = px + q

f(-1) = -p + q = -5
f(4) = 4p + q = 5
        ---------------------     - 
@ -5p = -10
@ p = -10/-5
@ p = 2

q :
-p + q = -5
-2 + q = -5
q = -5 + 2
q = -3

f(-6) = -6p + q
f(-6) = -6(2) + (-3)
f(-6) = -12 - 3
f(-6) = -15

Semoga membantu... ^_^