Let y be Justin base pay, w% be commission,
y + w%*600=350-----(1)
y+w%*900= 425-----(2)
From equation (1),
y = 350- w%*600 = 350-6w-------(3)
Substitute equation (3) into (2),
350-6w+9w=425
3w = 425-350= 75
w= 25
y = 350-6w= 350-6(25)= 200
so the function is base pay +25%of merchandise
Final answer is $ (200 + 0.25x)
