diketahui f(x)=mx+n. jika f(-1)=1 ,dan f(3)=9, maka f(1)-f(4) adalah

f(x) = mx + n
f(-1) = 1
m(-1) + n = 1
-1m + n = 1
f(3)= 9
m (3) + n = 9
3m + n = 9
-1m + n = 1
3m + n = 9 - ( dikurangi )
-4 m = - 8
m = -8 / -4
m = 2
substitusikan
-1m + n = 1
-1(2) + n = 1
-2+ n = 1
n = 1 + 2 = 3

F(1) = 2x + 3
2 (1) + 3 = 2 + 3
= 5
F (4 ) = 2x + 3
2(4) + 3 = 8 + 3
= 11

F(1) - F(4) = 5 - 11
= -6 《-6》