Question

Is (2,13) a solution to the equation y = 3x+7? Explain.

Answer 1

$13=3\cdot2+7\\ 13=6+7\\ 13=13 \Rightarrow \text{YES}$

Answer 2

$(x,y)=(2,13) \\ \\ \hbox{plug the values into the equation and check if it's true:} \\ 13=3 \times 2+7 \\ 13=6+7 \\ 13=13 \\ true$

(2,13) is a solution to the equation y=3x+7.