How do you solve the following system: 5x + 8y = -2, 6x+2y=-45x+8y=2,6x+2y=4?

1 Answer
Aug 31, 2017

See a solution process below:

Explanation:

Step 1) Solve the second equation for yy:

6x + 2y = -46x+2y=4

-color(red)(6x) + 6x + 2y = -color(red)(6x) - 46x+6x+2y=6x4

0 + 2y = -6x - 40+2y=6x4

2y = -6x - 42y=6x4

(2y)/color(red)(2) = (-6x - 4)/color(red)(2)2y2=6x42

(color(red)(cancel(color(black)(2)))y)/cancel(color(red)(2)) = (-6x)/color(red)(2) - 4/color(red)(2)

y = -3x - 2

Step 2) Substitute (-3x - 2) for y in the first equation and solve for x:

5x + 8y = -2 becomes:

5x + 8(-3x - 2) = -2

5x + (8 * -3x) - (8 * 2) = -2

5x - 24x - 16 = -2

(5 - 24)x - 16 = -2

-19x - 16 = -2

-19x - 16 + color(red)(16) = -2 + color(red)(16)

-19x - 0 = 14

-19x = 14

(-19x)/color(red)(-19) = 14/color(red)(-19)

(color(red)(cancel(color(black)(-19)))x)/cancel(color(red)(-19)) = -14/19

x = -14/19

Step 3) Substitute -14/19 for x in the solution to the second equation at the end of Step 1 and calculate y:

y = -3x - 2 becomes:

y = (-3 xx -14/19) - 2

y = 42/19 - 2

y = 42/19 - (19/19 * 2)

y = 42/19 - 38/19

y = 4/19

The Solution Is: x = -14/19 and y = 4/19 or (-14/19, 4/19)