How do you solve the following system?: 3x - 2y = 1 , 6x+5y=18

1 Answer
Mar 30, 2018

See a solution process below: (41/27, 16/9)

Explanation:

Step 1) Solve each equation for 6x:

  • Equation 1:

3x - 2y = 1

3x - 2y + color(red)(2y) = 1 + color(red)(2y)

3x - 0 = 1 + 2y

3x = 1 + 2y

color(red)(2) xx 3x = color(red)(2)(1 + 2y)

6x = (color(red)(2) xx 1) + (color(red)(2) xx 2y)

6x = 2 + 4y

  • Equation 2:

6x + 5y = 18

6x + 5y - color(red)(5y) = 18 - color(red)(5y)

6x + 0 = 18 - 5y

6x = 18 - 5y

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

2 + 4y = 18 - 5y

2 - color(red)(2) + 4y + color(blue)(5y) = 18 - color(red)(2) - 5y + color(blue)(5y)

0 + (4 + color(blue)(5))y = 16 - 0

9y = 16

(9y)/color(red)(9) = 16/color(red)(9)

(color(red)(cancel(color(black)(9)))y)/cancel(color(red)(9)) = 16/9

y = 16/9

Step 3) Substitute 16/9 for y in either of the equations in Step 1 and solve for x:

6x = 2 + 4y becomes:

6x = 2 + 4(16/9)

6x = (9/9 xx 2) + 64/9

6x = 18/9 + 64/9

6x = 82/9

6x = 82/9

1/6 xx 6x = 1/6 xx 82/9

6/6x = 82/54

x = 41/27

The Solution Is:

x = 41/27 and y = 16/9

Or

(41/27, 16/9)