Note that 3 - r = -r + 3 = -(r - 3). So the common denominator is just r - 3:

. . . . .

A useful method forsolving rational equationsis to multiply through by the common denominator. In this case, you would end up with:

. . . . .

. . . . .

Solve the linear equation. Remember to check the value of "r" in the original equation, to make sure there are no "division by zero" problems.