Answer:
x = (7ry -M)/(2r)
Step-by-step explanation:
This is a two-step linear equation in x, so is solved the way all 2-step equations are solved.
The x-term is found on the right side with another term. Step 1 is to add the opposite of the term not containing x:
M -7ry = 7ry -2rx -7ry . . . . . . add -7ry to both sides
M -7ry = -2rx . . . . . . . . . . simplify
The variable x has a coefficient that is not 1. To give it a coefficient of 1, we do Step 2: multiply by the inverse of the coefficient.
(M -7ry)(-1/(2r)) = (-2rx)(-1/(2r)) . . . . . multiply by the inverse of -2r
-(M -7ry)/(2r) = x . . . . . simplify a bit
x = (7ry -M)/(2r) . . . . . . eliminate the leading minus sign
