Answer:
-4 See Below:
Step-by-step explanation:
When you have a system of equations, you need to solve for one variable, and subsitute that variable into the other equation to solve for the other variables value.
3x +6y = 30 In this case, it would be easier to solve for x.
3x= 30-6y Divide both sides by 3
x= 10-2y
Now we substitute for x in the other equation.
5x- 4y = 22
5(10-2y)-4y=22
50-10y-4y=22
50-14y=22 Add 14y to both sides
50= 14y + 22 Subtract 22 from both sides
28 = 14y Divide by 14 on both sides.
y = 2
Substitute y=2 and solve for x.
x = 10- 2y
x= 10-2*2
x= 10-4
x= 6
Now we know y=2 and x=6, so we can substitute them into x-5y to find its value.
x - 5y
= 6-5*2
=6-10
= -4
