Two times a number added to another number is 25 three times the first number minus the other number is 20

Set up a system of equations to model this problem:

2x+y=25 (two times a number added to another number is 25)

3x-y=20 (three times the first number minus the other number is 20)

The easiest way to solve this system of equations would be to solve for y in the second equation, and substitute that value in for the first.

3x-y=20

*Subtract 3x from both sides*

-y=20-3x

*Divide both sides by -1*

y=3x-20

2x+y=25

2x+3x-20=25

*Combine likes terms*

5x-20=25

*Add 20 to both sides*

5x=45

*Divide both sides by 5*

x=45

Now, plug x into the first equation, and solve for y.

2x+y=25

2(45)+y=25

y=-65

Hope this helps!!

the answer is y < -3 or   y > 3

-3y > 7 + 2

-3 y > 9

y < -3