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Square Roots with Variables Calculator

Reviewed by Calculator Editorial Team

This calculator solves equations containing square roots and variables. It handles both simple and more complex cases, providing step-by-step solutions and visualizations when possible.

What is a Square Root with Variables?

Square root equations with variables involve expressions like √(x) = a or √(x + b) = c. These equations require special techniques to solve because the square root function is not linear.

Key properties of square roots that affect solving equations:

  • The square root function is defined only for non-negative numbers (√a is real only when a ≥ 0)
  • Square roots have both positive and negative roots (√a = ±b)
  • Isolating the square root is often the first step in solving such equations

Remember that √(a²) = |a|, not just a. The absolute value is important when dealing with squared terms under square roots.

How to Solve Square Root Equations

Step 1: Isolate the Square Root

Move all other terms to one side of the equation to isolate the square root term. For example:

√(x + 5) + 3 = 7 becomes √(x + 5) = 4

Step 2: Square Both Sides

Eliminate the square root by squaring both sides of the equation. Remember that squaring both sides preserves the equality.

√(x + 5) = 4 becomes x + 5 = 16

Step 3: Solve for the Variable

Perform algebraic operations to solve for the variable. In the example above:

x + 5 = 16 becomes x = 11

Step 4: Check for Extraneous Solutions

Square roots can introduce extraneous solutions that don't satisfy the original equation. Always verify your solution by plugging it back into the original equation.

For example, if you solve √(x) = -2, you get x = 4. But √4 = 2 ≠ -2, so x = 4 is an extraneous solution.

Worked Examples

Example 1: Simple Square Root Equation

Solve: √(x) = 5

  1. Square both sides: x = 25
  2. Check: √25 = 5 (valid solution)

Example 2: Equation with Addition Inside Root

Solve: √(x + 3) = 4

  1. Square both sides: x + 3 = 16
  2. Solve for x: x = 13
  3. Check: √(13 + 3) = √16 = 4 (valid solution)

Example 3: Equation with Negative Square Root

Solve: √(x) = -3

  1. Square both sides: x = 9
  2. Check: √9 = 3 ≠ -3 (extraneous solution)
  3. Conclusion: No real solution exists

FAQ

Can I solve equations with √(x) = a where a is negative?
No, because the square root of a real number is always non-negative. Equations like √(x) = -3 have no real solutions.
What if the equation has a square root on both sides?
You can still solve it by isolating one square root and then squaring both sides. Just be aware of potential extraneous solutions.
How do I handle equations with √(x) + √(y) = a?
These are more complex and typically require substitution or squaring both sides carefully. Our calculator handles these cases when possible.