Check the picture below.
let's recall that a kite is a quadrilateral, and thus is a polygon with 4 sides
sum of all interior angles in a polygon
180(n - 2) n = number of sides
so for a quadrilateral that'd be 180( 4 - 2 ) = 360, thus
![\bf 3b+70+50+3b=360\implies 6b+120=360\implies 6b=240 \\\\\\ b=\cfrac{240}{6}\implies b=40 \\\\[-0.35em] ~\dotfill\\\\ \overline{XY}=\overline{YZ}\implies 3a-5=a+11\implies 2a-5=11 \\\\\\ 2a=16\implies a=\cfrac{16}{2}\implies a=8](https://tex.z-dn.net/?f=%5Cbf%203b%2B70%2B50%2B3b%3D360%5Cimplies%206b%2B120%3D360%5Cimplies%206b%3D240%20%5C%5C%5C%5C%5C%5C%20b%3D%5Ccfrac%7B240%7D%7B6%7D%5Cimplies%20b%3D40%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Coverline%7BXY%7D%3D%5Coverline%7BYZ%7D%5Cimplies%203a-5%3Da%2B11%5Cimplies%202a-5%3D11%20%5C%5C%5C%5C%5C%5C%202a%3D16%5Cimplies%20a%3D%5Ccfrac%7B16%7D%7B2%7D%5Cimplies%20a%3D8)
Okay, so the equation for the y-intercept is y=mx+b, this will be your base for graphing anything.
For y = x + 3 it's basically y = 1x + 3. Use b as the y-intercept, or 3, and plot it as (x,y), (0,3). Then use m as the slope, or 1. 1 means positive one so the point goes (0,3), (1, 4), (2, 5).
For y = -3x - 1 it's the same thing but different numbers. Use b, the y-intercept, and plot it. -1 is b, so plot (0,-1). Then use the slope to go up or down the direction you need to go, or m. m is -3, so for every +1 in x, the y will decrease by 3. (0,-1), (0,-4), (0,-7).
I hope this helped in some way or increased your understanding!
Divide total bought by 3 and multiply by 20cents:
210/3 = 70
70 x 0.20 = $14.00
Subtract the amount they paid by the amount they made:
14.00 - 6.50 = $7.50
The profit made was: $7.50
3k + 10 = 22
3k = 22-10
3k = 12
k = 12/3
k = 4