Question

Simplify $\sqrt{x^8y^3z^5}$

Original question: Simplify. x8y3z5\sqrt{x^8y^3z^5} 42yz2 yz\sqrt{4^2yz^2}\ \sqrt{yz}

Expert Verified Solution

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Key takeaway: This problem uses the rule that square roots of perfect squares come out of the radical. Break each variable into an even-power part and a leftover part.

Step 1: Factor each exponent into an even part and a remainder

Assuming x,y,z0x,y,z\ge 0:

x8y3z5=x8y3z5\sqrt{x^8y^3z^5}=\sqrt{x^8}\,\sqrt{y^3}\,\sqrt{z^5}

Now simplify each factor:

  • x8=x4\sqrt{x^8}=x^4
  • y3=y2y=yy\sqrt{y^3}=\sqrt{y^2\cdot y}=y\sqrt{y}
  • z5=z4z=z2z\sqrt{z^5}=\sqrt{z^4\cdot z}=z^2\sqrt{z}

Step 2: Multiply the results

x8y3z5=x4yyz2z\sqrt{x^8y^3z^5}=x^4\cdot y\sqrt{y}\cdot z^2\sqrt{z}

=x4yz2yz= x^4yz^2\sqrt{yz}

Final answer

x4yz2yz\boxed{x^4yz^2\sqrt{yz}}


Pitfalls the pros know 👇 A frequent mistake is to write x8=x8\sqrt{x^8}=x^8. A square root cuts the exponent in half for perfect squares, so x8=x4\sqrt{x^8}=x^4, not x8x^8.

What if the problem changes? If the variables were not assumed nonnegative, then even roots would require absolute values for the fully extracted even powers, such as x8=x4\sqrt{x^8}=|x^4|. Under the usual assumption x0x\ge 0, this is simply x4x^4.

Tags: square root, perfect square, radical simplification

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