Price after off =80- 1/4 * 80 = 80-20 = $60
Coupon discount = 60*10/100 = $6
So, he have to pay, 60-6 = $54
155 degrees because the sum of the angles in a quadrilateral is 360 degrees.
x + 120 + 37 + 48 = 360
x= 155

The graph is attached below.
In order to find the y-intercept, check the graph and see where it hits the y-axis, so in this case the y-intercept would be at (0,6).
To find the x-intercept, check the graph and see where it hits the x-axis, and here it hits at x = -6.
Let s equal the number of shirts she can buy
140 > $28.50 + $20.75s
111.50 > 20.75s
5.37 > s
so we round down. she can buy 5 shirts, plus the one dress and she would spend less than $140