MathEquivalent ExpressionsMedium frequency

SAT Math: Simplify radical expressions and convert between radical and exponent form

22+ practice questions in Praczo

What you need to know

The concept, explained

  • 1

    √(ab) = √a · √b. Use this to pull perfect squares out: √50 = √(25 · 2) = 5√2.

  • 2

    Convert radicals to fractional exponents: √x = x^(1/2), ∛x = x^(1/3), x^(m/n) = ⁿ√(xᵐ).

  • 3

    When simplifying √(xⁿ), if n is even use x^(n/2); if odd, factor one x out: √(x⁵) = x²√x.

  • 4

    Rationalize denominators when needed: 1/√3 = √3/3. Multiply numerator and denominator by √3.

Common mistakes
  • Writing √(a + b) as √a + √b — this is WRONG. Radicals distribute over multiplication, not addition.
  • Forgetting that √x² = |x|, not x, when x could be negative (usually not tested, but worth knowing).
Try a sample question

SAT-style practice

Which expression is equivalent to √72?

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