Answer: Solving the equation for B, we obtain B=(R-Ax)/x (Third option)
Solution:
R=x(A+B)
Solving for B: Dividing both sides of the equation by x:
R/x=x(A+B)/x
R/x=A+B
Subtracting A both sides of the equation:
R/x-A=A+B-A
R/x-A/1=B
B=R/x-A/1
Subtracting the fractions on the right side of the equation:
B=(R-Ax)/x