Let the price of the computer = X
Store A is selling it for 25% off, so they are selling it for 75% of the original price, so you have 0.75X
Store B is selling it for 180 less the original price, so you have X - 180
Now set both equations to equal and solve for x:
0.75x = X-180
Subtract 1X from each side:
-0.25x = -180
Divide both sides by -0.25:
x = -180 / -0.25
X = 720
The original price is $720
check:
720 x 0.25 = 180