Question

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

Original question: They’re implicitly assuming x,y,z0x, y, z \ge 0. In this case, x8y3z5=x8y3z5.\sqrt{x^8y^3z^5}=\sqrt{x^8}\sqrt{y^3}\sqrt{z^5}. Consider how you can factor out the “largest” perfect square in each square root. You should be able to finish from here.

Expert Verified Solution

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Key takeaway: The statement points out the main strategy: factor out the largest perfect square from each square root, then combine what remains.

Step 1: Use the product rule for square roots

a

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

Because the variables are assumed to be nonnegative, we can simplify directly.

Step 2: Extract the largest perfect square from each factor

  • x8=(x4)2x^8=(x^4)^2, so x8=x4\sqrt{x^8}=x^4
  • y3=y2yy^3=y^2\cdot y, so y3=yy\sqrt{y^3}=y\sqrt{y}
  • z5=z4zz^5=z^4\cdot z, so z5=z2z\sqrt{z^5}=z^2\sqrt{z}

Step 3: Combine the outside factors and inside factors

x8y3z5=x4yz2yz\sqrt{x^8y^3z^5}=x^4yz^2\sqrt{yz}

Final answer

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


Pitfalls the pros know 👇 The main trap is stopping after simplifying only one factor. You need to simplify all three radicals and then combine the leftover radicals under one square root.

What if the problem changes? If one of the exponents were even, such as z4z^4 instead of z5z^5, then z4=z2\sqrt{z^4}=z^2 and no z\sqrt{z} would remain. The leftover radical comes only from odd exponents.

Tags: perfect square, product rule, radical expression

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