Question

Solve the system of equations by graphing. x+y=-9 4x+y=-19

Answer 1

For this case we have the following system of equations:

$x + y = -9\\4x + y = -19$

We multiply the first equation by -4:

$-4x-4y = 36$

We have the following equivalent system of equations:

$-4x-4y = 36\\4x + y = -19$

We add the equations:

$-4x + 4x-4y + y = 36-19\\-3y = 17\\y = - \frac {17} {3}$

We find the value of the variable "x":

$x = -9-yx = -9 - (- \frac {17} {3})\\x = -9 + \frac {17} {3}\\x = \frac {-27 + 17} {3}\\x = - \frac {10} {3}$

Thus, the solution of the system is:

$(x, y): (- \frac {10} {3}, - \frac {17} {3})$

See the graphic in the attached image

ANswer:

$(x, y): (- \frac {10} {3}, - \frac {17} {3})$

See the graphic in the attached image