let
d = cost of a computer desk
c = cost of an office chair
4d + 3c = 1110
2d + 5c = 940
multiply (2nd) equation by 2
4d + 3c = 1110
4d + 10c = 1880
------------------------subtract
-7c = - 770
c = 110
2d + 5c = 940
2d + 5(110) = 940
2d = 550 = 940
2d = 390
d = 195
answer
cost of a computer desk = $ 195
