Is (-3,7) a solution for the equation y=4x+15

No, it is not. To solve this problem, you take the numbers in the coordinate pair and insert them into the equation, putting the x coordinate in place of x and the same with the y coordinate and place. When you insert the numbers, it comes out to be 7=4 (-3) + 15. since - 12 + 15 does not equal 7, then this coordinate is not a solution because when you put the coordinate into the equation, it has to be true