We are given with the equation (a-c)/(x-a) = m. In this case, to isolate x, we can use the division, multiplication, addition adn subtraction properties. In this case, Divide the whole equation by m, to give, (a-c)/(x-a)/m = 1. Then multiply by (x-a). Then to isolate x, add a. this results to
x = [(a-c)/m]