Respuesta :

the dryer costs 900 because you subtract 942 from 42 and you get the total of the dryer. 
w + d = 942
w = d + 42

d + 42 + d = 942
2d + 42 = 942
2d = 942 - 42
2d = 900
d = 900/2
d = 450 <=== dryer costs $ 450

w = d + 42
w = 450 + 42
w = 492 <=== washer costs $ 492