What is the equation for:
slope: -2
ordered pair: (4,2)

y=x-4

Step-by-step explanation:

First you set the pair and slope into slope intercept form: y-2=-2(x-4)

Then you would distribute the slope: y-2=-2x+8

Lastly, you would divide everything by -2:  y=x-4

Find out the  what was the original price of her purchase .

To prove

Let us assume that the original price of her purchase be x.

As given

A store is having a 20%-off sale on all merchandise. If Mai buys one item and saves $13 .

20% is written in the decimal form.

= 0.20

Than the equation becomes

x × 0.20 = 13

x = $65

Therefore the original price of her purchase is $65.