D'oh!, of course zeroth, make sure you copy down the problem right :-)
First, Combine like terms:
y = (x * .4175) + x = 1.4175 * x
y = 1.4175 * x
Second,
solve for x (get x by itself):
Multiply both sides by (1/1.4175)
(1/1.4175) * y = (1/1.4175) * 1.4175 * x
y / 1.4175 = (1) * x
x = y / 1.4175
Finally, substitute in your value for y:
x = 874.90/1.4175 = 617.2134ish
(or 8749000 / 14175 = 349960 / 567 if that's how you roll)