An equation of a line that goes throught the points (-10,4) and (-6,2) is Y = -1/2X - 1.
To find this, you must first find the slope. In doing so, you use the formula X2 - X1/ Y2 - Y1 (2 - 4)/(-6 + 10). The reason you would add 10 instead of subtract 10, is due to the fact you're subtracting a negative. Therefore, making it "+ 10". Solve the top and bottom, and you'll get -2/4, which simplified is -1/2.
Next, you pick a pair of coordinate point. This is used to help you find the "B" value if the equation. In this case, I used (-6,2). Fill in the formula Y = MX + B with the coordinate points, and the slope (2 = -1/2*(-6) + B), then solve. Multiply -1/2 by -6 to get 3, then subtract 3 from both sides, leaving -1 = B.
Finally, fill in Y = MX + B with the slope (M) and the y-int (B). Thus making the answer Y = -1/2X - 1. Here's a graph with the coordinate points and the line equation to show this is correct.
I hope this helps!