persamaan fungsi didefinisikan dengan rumus f(x)=mx + n. jikaf(3)= -10 dan f(-2)=0 maka nilai (-7) adalah

f(3) = 3(m) + n = -10
f(-2) = -2(m) + n = 0
________________ -
                 5m = -10
                 m = -2

3(-2) + n = -10
-6 + n = -10
n = 4

f(-7) = -2(-7) + 4
        = 14 + 4
        = 18

dik : f(3) = -10
f(-2)= 0
f(x) = mx + n
dit: f(-7)
jawab :
f(3) = m(3)+ n
-10 = 3m + n ............ (1)


f(-2) = m(-2)+n
0 = -2m + n ............ (2)

eliminasi
3m + n = -10
-2m + n = 0
___________ _
5m = -10
m = -2

substitusikan nilai m ke pers. 1
-10 = 3(-2) + n
-10 = -6 + n
n = -4

f(-7) = m(-7)+n
f(-7) = -2(-7) -4
f(-7) = 14 -4
f(-7) = 10