3x + 4y = 15
(3x - y = 30
Enter the solution as an ordered pair.
The solution is

x = 9

y = -3

Step-by-step explanation:

i will solve this equation simultaneously using the substitution method

so let

3x + 4y = 15 equation 1

3x - y = 30 equation 2

from equation 2

3x - y = 30 equation 2

y = 3x -30 equation 3

substitute for the value of y in equation 1

3x + 4y = 15 equation 1

3x + 4( 3x -30)= 15

3x + 12x- 120 = 15

15x - 120 = 15

15x = 15 + 120

15x = 135

divide both sides by 15 which is the coefficient of x

15x/15 = 135/ 15

x = 9

put the value of x in equation 3

y = 3x -30 equation 3

y = 3(9) - 30

y = 27 - 30

y = -3

75

step-by-step explanation: