<h2>
Answer:</h2>
<u>24.</u>
<h2>
Step-by-step explanation:</h2>
<h3>1. Write the expression.</h3>

<h3>2. Substitute the variables by the respective given value using <u>parenthesis</u>.</h3>

<h3>3. Simplify the expression by applying the hierarchy or mathematical operations.</h3>
<em>a) Solve parenthesis.</em>

<em>b) Solve the exponent.</em>

<em>c) Divide.</em>

<em>d) Subtract.</em>

<span>Complete the following direct proof.
1) Triangles are the only polygons with three sides.
2) The polygon has three sides.
3) Thus, triangles are polygons.
</span>