solve the system of equation 2x-9y=14 x=-6y+7

You know the value of x: -6y +7
So you can replace the x in the first equation:
2*(-6y+7)-9y = 14 
distributive law
-12y+14-9y = 14
-21y+14=14
-14
-21y = 0
:(-21)
y = 0
Now you replace the y in the seccond equation with 0
x = -6*0+7
x = 7

ANSWER: x is 7 and y is 0