y = T(x) = A x + b    f(x) = 3x + 2

 [y1] = [a11 a12] [x1] + [b1]
 [y2] = [a21 a22] [x2]   [b2]

Vertex 1:

 [0] = [a11 a12] [1] + [b1]
 [0] = [a21 a22] [0]   [b2]

Vertex 2:

 [-1] = [a11 a12] [2] + [b1]
 [ 0] = [a21 a22] [0]   [b2]

Alternate solution:

 y = Ax + b
 y - b = Ax
 A^1(y - b) = x