If you make a 25% of discount how much money do you subtract?

Lets say u want an item that originally cost $ 50and u get a 25% discountthen u are actually subtracting 25% of the original price.

25% of 50 turn the percent to a decimal..." of " means multiply
0.25 * 50 = 12.50so u would be subtracting 12.50 from $ 50 for the discounted price which is (50 - 12.5) = 37.5

here is another example...
u want an item that costs $ 90and it is 25% offso u would be subtracting (25% of 90)u would be subtracting (0.25 * 90) = 22.50 from the original price to arrive at the discounted price.
90 - 22.50 = 67.50...the discounted price

But let me show u somethingtaking 25% off is the same as paying 75%..
so lets say u want an item that costs $ 60and u get a 25% discount...this means u r actually paying 75%ur paying 75% of 60.
0.75 * 60 = $ 45...this is what u r payingno need for subtracting 

the formula of a slope:

we have the points (-2, 7) and (2, 3). substitute:

answer: the slope is equal -1.