Answer:
c = 2.5 , d = - 3
Explanation:
f(x) = cx + d
f(4) = 7 ( substitute x = 4 into the equation and equate to 7 )
f(10) = 22 ( substitute x = 10 into the equation and equate to 22 )
4c + d = 7 → (1)
10c + d = 22 → (2)
subtract (1) from (2) term by term to eliminate d
(10c - 4c) + (d - d) = 22 - 7 , that is
6c = 15 ( divide both sides by 6 )
c = 2.5
substitute c = 2.5 into (1) and solve for d
4(2.5) + d = 7
10 + d = 7 ( subtract 10 from both sides )
d = - 3