Solve the System of Equations 4x-y = -7 x + 3y = -5

To find a solution to the system of equations:

4x – y = -7;

x + 3y = -5,

we must first of all decide on the method of solving it. Let’s use the substitution method to solve the system. And we start with the expression from the first equation of the system of the variable y through x.

System of equations:

x + 3y = -5;

y = 4x + 7.

We substitute in the first equation instead of y the expression from the second equation and we get the system:

x + 3 (4x + 7) = -5;

y = 4x + 7.

We solve the resulting first equation:

x + 12x + 21 = -5;

13x = -26;

x = -2.

System:

x = -2;

= 4 * (-2) + 7 = -1.