#### Multiple Choice Question (MCQ)

What is the solution set to the equation 4+x^2=2x^2-5 ?

1. ×

\{x:x=3\}

2. ×

\{x:x=-3\}

3. \{x:x=\pm3\}

4. ×

\{x:x=-1\}

5. ×

\{x:x=1\}

Collected in the board: Algebraic equation

Steven Zheng posted 1 year ago

1. A solution set is the set of variables that makes the equation true. For a quadratic equation, it has either 2 duplicate roots(1 solution) or distinct roots.

Solving the equation gives

4+x^2=2x^2-5

x^2=9

Taking the square roots

x=\pm3

It turns out the equation has two distinct solutions. So the solution set of the equation is \{x:x=\pm3\} .

C is the correct choice.

Steven Zheng posted 1 year ago

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