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Solving Radical Equations - Problem 1 7,705 views

Teacher/Instructor Alissa Fong
Alissa Fong

MA, Stanford University
Teaching in the San Francisco Bay Area

Alissa is currently a teacher in the San Francisco Bay Area and Brightstorm users love her clear, concise explanations of tough concepts

Think back to when you were first learning how to solve equations. What your teacher probably talked about is undoing what was being done to x. In this problem x is being square rooted and also multiplied by 4. I have to undo those by taking the opposite mathematical operation.

Well the opposite of square rooting is to square something right? So what I’m going to do is square both sides of this equation, so I’ll have 4x is equal to 9. From there you guys know what to do. 4 is being multiplied by x, so you divide both sides by 4 and you’ll get x is equal to 9/4. That’s the final answer. You can leave it in fractional form or turn it into a decimal it’s up to you. I’m going to go back and check and just make sure that makes sense.

To check what I’m going to do is substitute in there to make sure that 4 times 9/4 when I reduce that fraction I do indeed get the answer 3. Sweet that means I did it right. So again what I did was undo the square rooting by squaring both sides of the equation.