tolong bantuin ya kak

f(x) = px + q
f(7/5) = 7/5 p + q = 7
------------------------------(×5)
f(7/5) = 7p + 5q = 35

f(1/5) = 1/5 p + q = 13
------------------------------(×5)
f(1/5) = p + 5q = 65

7p + 5q = 35
p + 5q = 65
------------------- ( - )
6p = - 30
p = - 5

p + 5q = 65
- 5 + 5q = 65
5q = 70
q = 14

b) f(x) = - 5x + 14

c) f(-3/5) = - 5 . - 3/5 + 14 = 3 + 14 = 17