Using elimination method. Using substitution will cause some fraction problems.
c- child tickets
a- adult tickets
4a + 7c = $83
5a + 6c = $90
multiply by -5
-20a - 35c = -$415
20a + 24c = $360
-11c= -$55
c = $5 child tickets
4a + 7(5)= $83
4a + 35 = $83
4a = $48
a= $12 adult tickets
(8)(-4.5) is not equivalent because 8 times -4.5 results in negative value
3y=x-3
y=1/3x-1
Perpendicular slope: -3
y=-3x+b
Plug in the coordinates in the equation:
-9=-3(5)+b
-9=-15+b
4=b
Equation: y=-3x+4
Also, when finding the perpendicular slope you take the reciprocal of the original slope and make it negative if it is positive and make it positive if it’s negative.
I think that the best answer here would be that A = 40 degrees.
1/20 is the fraction that you'll have left
