Question

If 5x−4y=22 and 3x+6y=30, what is the value of x−5y

Answer 1

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