8x - 7y = 10
In place of the x write (
).
In place of the y write (-1):
8(
) - 7(-1) = 10
Now simplify: 8(
) is 3 because the 8's cancel, and
-7(-1) becomes +7, so we have:
3 + 7 = 10
10 = 10
Since the end result is the same number on both sides of
the equal sign, that tells us that (
,-1) is a
solution to the equation 8x - 7y = 10.
Edwin