Rearrange the formula F = mg + ma for a.

draw out a triangle and then create three boxes inside by drawing a T. In each of the boxes you've created you need to put one of the letters from the equation. The equation you currently have is F = m*a. To rearrange this equation put the m and the a into the bottom boxes and the F above. Because there is a vertical line between the m and the a, this means you times them. If there is a horizonal line between two letters you divide them. So to find a, you must divide F by m.