Answer:
(-3,-6)
Explanation:
A system of equations is 2 or more equations for which the same x,y solution exists. We can solve the system in three ways: elimination, substitution, or graphing. Substitution can be used by substituting the value of one variable into the equation.
We can solve for y in 6=-4x+y. 6+4x=y.
Because y=6+4x, we can substitute 6+4x into y in -5x-y=21.
-5x-y=21
-5x-(6+4x)=21
-5x-6-4x=21
-9x-6=21
-9x=27
x=-3
We now substitute x=-3 into y=6+4x.
y=6+4x
y=6+4(-3)
y=6-12
y=-6