First you have to put it into point-slope form before you can write it in slope-intercept form which is y-y1=m(x-x1)
Y-1=2(x-1)
Distribute the 2 to the x and -1
Y-1=2x-2
Move it all to one side
Y=2x-1
Price after off =80- 1/4 * 80 = 80-20 = $60
Coupon discount = 60*10/100 = $6
So, he have to pay, 60-6 = $54
26. y= -7/3+ 0 or just y= -7/3
27. y= -10
S= R- 1/3R
The first problem s=18 r-= 6
This is how it works
Use S-= R-1/3R
12= 18-1/3(18)
12= 18-6
12=12
Divested using long division
1810 r 3