Q. What is the solution of the equation \(x^2 = 64\)?

Answer

Taking square roots: \(x=\pm\sqrt{64}=\pm 8\). Thus \(x=8\) or \(x=-8\).

Detailed Explanation

Problem

Solve the equation

\(x^{2} = 64\)

Step-by-step solution

  1. Recognize the equation. We are given the quadratic equation

    \(x^{2} = 64\).

  2. Bring all terms to one side (optional, useful for factoring):

    \(x^{2} – 64 = 0\).

    This expresses the equation in the standard form “something equals zero”, which allows using the zero-product property after factoring.

  3. Factor the difference of squares. Use the identity \(a^{2}-b^{2}=(a-b)(a+b)\). With \(a=x\) and \(b=8\) we get

    \(x^{2}-64 = (x-8)(x+8)\).

  4. Apply the zero-product property: if a product of two real numbers is zero, then at least one factor is zero. Thus

    \((x-8)(x+8)=0\)

    implies either

    \(x-8=0\)

    or

    \(x+8=0\).

  5. Solve each linear equation:

    If \(x-8=0\) then \(x=8\).

    If \(x+8=0\) then \(x=-8\).

  6. Alternatively, use the square-root property: for a nonnegative number \(a\), the solutions of \(x^{2}=a\) are \(x=\pm\sqrt{a}\). Applying this with \(a=64\) gives

    \(x=\pm\sqrt{64}=\pm 8\).

  7. Check both solutions by substitution:

    For \(x=8\): \(8^{2}=64\), so it satisfies the equation.

    For \(x=-8\): \((-8)^{2}=64\), so it also satisfies the equation.

  8. Conclusion: the solutions are

    \(\boxed{x=8}\) and \(\boxed{x=-8}\).

    As a solution set: \(\{ -8,\, 8 \}\).

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FAQs

What is the solution of \(x^2=64\)?

\(x=\pm 8\). Both \(8\) and \(-8\) satisfy \(x^2=64\).

Why are there two solutions?

Squaring an integer loses sign information: both \(8\) and \(-8\) square to \(64\). Even-power equations typically give two real roots (counting sign).

How do you solve it step-by-step?

Isolate and take square roots: \(x^2=64\) → \(x=\pm\sqrt{64}\) → \(x=\pm8\). Or factor: \(x^2-64=(x-8)(x+8)=0\).

Why not just \(x=8\) when using \(\sqrt{64}\)?

The principal square root \(\sqrt{64}=8\) is nonnegative; solving \(x^2=64\) requires both signs, hence \(x=\pm\sqrt{64}\).

How does factoring work here?

Write \(x^2-64=0\). Factor as \((x-8)(x+8)=0\). Set each factor zero: \(x=8\) or \(x=-8\).

Are there complex solutions?

Are there complex solutions?

How can I check my answers?

Substitute: \(8^2=64\) and \((-8)^2=64\). Both satisfy the equation, so they are correct.

What about multiplicity of roots?

Each root here has multiplicity 1. If the equation were \((x-8)^2=0\), then \(x=8\) would be a double root (multiplicity 2).
The solutions are x = 8 and x = -8.
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