Answer:
-181 - 79x
Explanation:
I am not sure your comment fits the given problem.
I get the following approach and solution :
T(1 + 4x) = 1×a + 4x×b = 2 + 2x
a = 2 + 2x - 4xb
T(4 + 15x) = 4×a + 15x×b = -3 + 3x
4×(2 + 2x - 4xb) + 15xb = -3 + 3x
8 + 8x - 16xb + 15xb = -3 + 3x
11 + 5x - xb = 0
11 + 5x = xb
b = (11 + 5x)/x
a = 2 + 2x - 4x(11 + 5x)/x = 2 + 2x - 44 - 20x = -42 - 18x
T(3 - 5x) = 3×a - 5xb = 3(-42 - 18x) - 5x(11 + 5x)/x =
= -126 - 54x - 55 - 25x = -181 - 79x
control :
T(1 + 4x) = a + 4xb = -42 - 18x + 44 + 20x = 2 + 2x
T(4 + 15x) = 4a + 15xb = -168 - 72x + 165 + 75x = -3 + 3x