Raymond B. answered 03/24/22
Math, microeconomics or criminal justice
two equations, two unknowns can be solved by substitution and elimination or matrix algebra
it also sometimes helps to graph the two equations and see where they intersect
y = (1/3)x -1
3y = x-3
x = 3y+3
5x=9y
5(3y+3) = 9y
15y +15 = 9y
6y = -15
y =-15/6 = -5/2 = -2.5
x =3y+3 = 3(-5/2)+3 = -15/2 +3 = -9/2 = -4.5
graphically, the point of intersection of the two lines is (-4.5, -2.5)
check the answer by plugging that point into each equation, x= -4.5, y =-2.5
y= (1/3)x -1
-2.5 = (1/3)(-4.5) -1 = -1.5 -1 -2.5
5x = 9y
5(-4.5) = 9(-2.5)
-22.5 = -22.5