Okay, so this is known as a system of equations.
Also, putting a 1 in front of a variable is unnecessary, as that is a given.
-y - x = 3
-6x - 5y = 24
In the first equation, add x to both sides.
-y = 3 + x
Multiply all terms by -1.
y = -3 - x
Now that we have a value of y we can plug it into the second equation to solve for x.
-6x - 5(-3 - x) = 24
Distributive property.
-6x + 15 + 5x = 24
Combine like terms.
-x + 15 = 24
Multiply all terms by -1.
x - 15 = -24
Add 15 to both sides.
x = -9
Now that we have a value for x, we can plug it into the first equation to solve for y.
y = -3 - (-9)
y = -3 + 9
y = 6