solve the equations using substitution

Question

2x + 3y = 9
3x + 4y = 5

Answer 1

The equations are  2x + 3y = 9 and  3x + 4y = 5.

2x + 3y = 9

multiply the equation by 3.

6x + 9y = 27----------> 6x = 27 -9y

3x + 4y = 5

multiply the equation by 2.

6x + 8y = 10

substitute 6x = 27 -9y in the equation 6x + 8y = 10.

27 -9y +8y = 10

27 - y = 10

-y = -17

y = 17

substitute y = 17 in 2x + 3y = 9.

2x + 3 * 17 = 9

2x = 9- 51 = -42

x = -21

(x, y) = (-21, 17).