[tex]\text{First, simplify the equation:}\\\\5x+5y=25\\\\\text{Subtract 5x from both sides}\\\\5y=-5x+25\\\\\text{Divide both sides by 5}\\\\y=-x+5\\\\\text{The slope of the line is -1, so this is a linear equation, due to the fact}\\\text{that the slope is at a constant "rate of change"}\\\\\boxed{\text{Yes, it's a linear equation}}[/tex]
