Question
Solve. (Enter your answers as a comma-separated list. If there is no solution, enter NO SOLUTION.)
Original question: Solve. (Enter your answers as a comma-separated list. If there is no solution, enter NO SOLUTION.)
LEARN IT: SOLVE RATIONAL EQUATIONS BY MULTIPLYING BY THE LCD OF THE RATIONAL EXPR
Expert Verified Solution
Key takeaway: This is a rational equation with one denominator, so the fastest method is to multiply every term by the LCD and reduce it to a polynomial equation.
Step 1: Find the restriction
The denominator is , so
Step 2: Multiply by the LCD
Multiply both sides by :
This simplifies to
Step 3: Expand and solve
Step 4: Check the restriction
Neither nor makes , so both are valid.
Answer: -7, 7
Pitfalls the pros know 👇 Do not forget the restriction . Also, when you solve , remember that square roots give two answers: and .
What if the problem changes? If the right-hand side were different, the same LCD method would still work. The final step would depend on whether the reduced equation factors, becomes quadratic, or has no real solutions.
Tags: LCD, quadratic equation, restriction
FAQ
What are the solutions to this rational equation?
The solutions are x = -7 and x = 7. First multiply both sides by x + 2, then solve the resulting quadratic equation, and finally check that x = -2 is not used.
Why are there two answers?
Because the equation reduces to x^2 = 49, and a quadratic of this form has two square-root solutions: x = 7 and x = -7.