Let w = washer and d = dryer:
w + d = $770,
but w = d + 70, replace w with d+70
(d+70) + d = 770
2d + 70 =770
2d = 770 -70 = 700
and d=$350, then w=350+70 = 420
The decimal is irrational because it is not repeating.
-2/3
rise over run. plot the points and count.