You can
put this solution on YOUR website!the "letter" is the "unknown" in an equation. It is the thing you are trying to find the value(s) of.
Evaluate means work out, eg Evaluate 3(2x-5) when x=4, gives 3(2(4)-5), which is 3(8-5), which is 3(3) which is 9.
Simplify means just that, eg Simplify 3x-4y+2x-5xy gives 5x-4y-5xy
Solve means find the "roots" of the given equation. This is any points that satisfy y=0. In other words, find the value(s) of x where the equation crosses the x-axis.
jon.