So, first you need to replace the variables ( x and y) for numbers. In this case, the numbers are 7 for x and 14 for y. Now that you replaced the numbers for the variables, the equation looks like this: -5x7+3x14=7. To make sure the equation is correct, you need to multiply -5x7 (which is -35), then you need to multiply 3x14 (which is 42). Now, you need to add -35+42, which gives us 7. So, the equation is correct.
You are given the equation and points (x, y) to plug into that equation. See which ones satisfy. The left side must equal the right side (7 in this case) when evaluating...
-5(7) + 3(14) = 7
-35 + 42 = 7
7 = 7
The point (7, 14) works. The other points will not yield the same result..
