How do you solve the following system?: x + 2y = -2 , x – 3y = -12

1 Answer
Jun 20, 2018

See a solution process below:

Explanation:

Step 1) Solve each equation for x:

  • Equation 1:

x + 2y = -2

x + 2y - color(red)(2y) = -2 - color(red)(2y)

x + 0 = -2 - 2y

x = -2 - 2y

  • Equation 2:

x - 3y = -12

x - 3y + color(red)(3y) = -12 + color(red)(3y)

x - 0 = -12 + 3y

x = -12 + 3y

Step 2) Because the left side of both equations are the same we can equate the right sides and solve for y:

-2 - 2y = -12 + 3y

-2 + color(blue)(12) - 2y + color(red)(2y) = -12 + color(blue)(12) + 3y + color(red)(2y)

10 - 0 = 0 + (3 + color(red)(2))y

10 = 5y

10/color(red)(5) = (5y)/color(red)(5)

2 = (color(red)(cancel(color(black)(5)))y)/cancel(color(red)(5))

2 = y

y = 2

Step 3) Substitute 2 for y in the solutions to either of the equations in Step 1 and calculate x:

x = -12 + 3y becomes:

x = -12 + (3 xx 2)

x = -12 + 6

x = -6

The Solution Is:

x = -6 and y = 2

Or

(-6, 2)