Question 1190677
your equations are:


2x + y = -4
x + y = -7


solve for x in the second equation to get:


x = -7 - y


replace x in the first equation with that to get:


2x + y = -4 becomes  2 * (-7 - y) + y = -4.


you have just changed one equation with two variable into one equation with one variable, allowing you to solve for that variable.


the equation to solve is:


2 * (-7 - y) + y = -4.
simplify to get:
-14 - 2y + y = -4
combine like terms to get:
-14 - y = -4
add 14 to both sides to get:
-y = -4 + 14
simplify to get:
-y = 10
multiply both sides by -1 to get:
y = -10


now that you solved for y, you can go back to your original equations to solve for x.

your original equations are:
2x + y = -4
x + y = -7


when y = -10 .....
2x + y = -4 becomes 2x -10 = -4 which becomes 2x = 6 which becomes x = 3.
x + y = -7 becomes x - 10 = -7  which becomes x = 3.
your solution is that y = -10 and x = 3.
both original equations are true with those values for x and y.


let me know if you have any questions or need further clarification.


here's a reference for you as well.
<a href = "https://www.purplemath.com/modules/systlin4.htm" target = "_blank">https://www.purplemath.com/modules/systlin4.htm</a>
theo