Question 70081
To determine if the ordered pair is a solution to an equation, just plug the x and y values
of the ordered pair into the equation and see if the left side of the equation still 
equals the right side.  

So, is the ordered pair (1,-5) a solution to the equation 4x-4 = 9?  Note that there is
no "y" term in the equation, so we do not need to be concerned with the value -5 in the
ordered pair. We only need to substitute the x value of the ordered pair into the equation.
So in place of the x in the equation we let x = 1 from the ordered pair.  This makes the
equation:
4*(1) - 4 = 9
Simplifying this by doing the multiplication we get:
4 - 4 = 9
which further simplifies to 0 = 9.  This obviously is not true.  Therefore, the ordered
pair (1, -5) is not a solution to the equation 4x - 4 = 9

In the off chance that you meant the equation to be 4x - 4y = 9, if you substitute 
1 for x and -5 for y the equation becomes:
4*(1) - 4*(-5) = 9
After the multiplications are done the equation is:
4 + 20 = 9
This is not true so the ordered pair (1, -5) is not a solution to the equation 4x - 4y = 9 either.

Next, is the ordered pair (1, -5) a solution to the equation 2x + 3y= -13.  The same
process is used.  From the ordered pair we get the values x = 1 and y = -5.  Substitute
those values for x and y in the equation.  When they are substituted the equation 
becomes:
2*(1) + 3*(-5) = -13

By doing the multiplications this equation becomes:

2 - 15 = -13

which further simplifies to:

-13 = -13

This is true so the ordered point (1, -5) is a solution to the equation 2x + 3y = -13.

Hope these two examples are enough for you to see how to determine if an ordered pair is
a solution to an equation.