Y = 2x + 3
First, find the y-intercept (b). This is where the line meets the y-axis. The line meets the y-axis at 3, so the y-intercept is 3.
Now, find the slope (m) of the line. Slope is rise divided by run. The line goes up by 2, over by 1, up by 2, over by 1, and so on. So, the rise is 2 and the run is 1. 2 divided by 1 is 2, so the slope is 2.
Put these together into the equation to get y = 2x + 3.
Let the medium angle be B degrees
the small angle be A degrees
the large angle be C degrees
Then
C = 2 B + 20 ..................X
5 B = A + C ..................Y
Sum of all angles
A + B + C = 180 .............Z
Applying Y in Z
5 B + B = 180
6 B = 180
B = 30
From X C = 2 x 30 + 20 = 60 + 20 = 80
From Y 5 x 30 = A + 80
150 = A + 80
150 - 80 = A = 70
Hence medium angle B = 30 degrees
the small angle A = 70 degrees
the large angle C = 80 degrees
2x + 3y = -21
2x = -21 - 3y
x = -10.5 - 3/2y
-10x + 2y = 20
-10(-10.5 - 3/2y) + 2y = 20
105 + 15y + 2y = 20
105 + 17y = 20
17y = -85
y = -5
2x + 3y = -21
2x + 3(-5) = -21
2x - 15 = -21
2x = -6
x = -3
Therefore, the coordinates are (-3, -5).