diketahui rumus syatu fungsi f(x)=ax+b,f(3)=5dan f(-1)=-3 nilai f(4) adalah

f(x) = ax + b
f(3) = 5
f(-1) = -3

3a + b = 5
-a + b  = -3
--------------------- -
4a = 8
a = 8/4
a = 2

3a + b = 5
3(2) + b = 5
6 + b = 5
b = 5 - 6
b = -1

f(4) = 2(4) - 1
f(4) = 8 - 1
f(4) = 7