show your work: Solve using combination method 3x+y=4 2x+y=5

y=7

Step-by-step explanation:

Multiply each equation by the value that makes the coefficients of y opposite.

3x+y=4

(−1)⋅(2x+y)=(−1)(5)

Simplify.

3x+y=4

−2x−y=−5

Add the two equations together to eliminate y from the system.

     3x+y=4

+−2x−y=−5

     x  =   −1

Substitute the value found for x into one of the original equations, then solve for y

3(−1)+y=4

Multiply 3 by −1

−3+y=4

Move all terms not containing y to the right side of the equation.

Add 3 to both sides of the equation.

y=4+3

Add 4 and 3

y=7