Question

Find the solution to the following system of equations.
2x + y = 7
x – y = -4

Answer 1

here we go again... you can add both equation and eliminate y then solve for x...

Answer 2

2x + y + x - y = 7 + 4
3x = 11
or
x = 11/3

Answer 3

you can use either of the two given equations to solve for y by plug-in x...

Answer 4

easier to use 2nd equation:
x - y = 4
11/3 - y = 4
or
y = 11/3 - 4
y = (11 - 4(3))/3
y = (11 - 12)/3
y = -1/3

Answer 5

you can check by plug-in both to equation 1 if both x and y satisfy the equation...

Answer 6

2x + y = 7
2(11/3) + (-1/3) ?= 7
22/3 - 1/3 ?= 7
(22 - 1)/3 ?= 7
21/3 ?= 7
7 = 7.... check they are equal