Let x = the original price.
With 25% off, the price drops to
0.75x.
With another 5% off, the price drops to
0.95*(0.75x) = 0.7125x
Add 8.25% tax, and the price goes up to
1.0825*(0.7125x) = 0.7713x
This is equal to the amount paid, so
0.7713x = 384.87
x = 384.87/0.7713 = $498.99
Answer: Original price = $498.99
There are no "of the following" listed, but when you multiply a length by 2/3, you're indicating that you are only "using" 2/3 of that length, which is smaller by a third. Regardless of what your original lengths of the diagonals are, the area is going to be smaller. By 2/3, to be exact.
Okay. The question is m/9 - 17 = 21. First off, we will add 17 to both sides. -17 + 17 cancels out. 21 + 17 is 38. That leaves m/9 = 38. Multiply each side by 9 to isolate the m, because m is the numerator and 9 is the denominator. m/9 * 9/1 cancels out. 38 * 9 is 342. Let's check this. 342/9 is 38. 38 - 17 is 21. 21 = 21. There. x = 342.
