Question 106863
Is (-1, 2) a solution of {{{y = (1/2)x-1}}}?
You can find out by simply substituting the x- and y-coordinates of the given point into the equation. If the equation is still valid (the two sides are equal) then the point is a solution; if it isn't then it aint!
Let's try it.

{{{2 = (1/2)(-1)-1}}} Simplify.
{{{2 = (-1/2)-1}}}
{{{2 = -1.5}}} No cigar!
The given point is not a solution of {{{y = (1/2)x-1}}}