identity property=something times one
You can focus on the two sub-triangles ABC and ACD
We know that they are both right triangles, because we're given that AC and BD are perpendicular.
The sides AB and AD are the hypothenuses of these triangles, so we know their length through the pythagorean theorem:


But since we're given
, the expressions for AD and AB are actually the same expression. This proves that AD=AB, and thus that the triangle is isosceles.
Answer:
probability the student plays both instruments is [
]
<h2>
<u>
Explanation</u>
:</h2>
students who play both instruments = total students - flute players - piano players - students who play neither instruments
students who play both instruments
→ 31 - 4 - 14 - 7
→ 6 students play both instruments.
probability:
<h2>→

</h2><h2>→

</h2>
<em>*To solve for a specified variable, you need to isolate that variable onto one side.</em>
<h3>11.</h3>
Firstly, subtract 5r on both sides: 
Lastly, divide both sides by 2 and <u>your answer will be
</u>
<h3>12.</h3>
First, subtract z on both sides of the equation: 
Next, divide both sides by y and <u>your answer will be
</u>
<h3>13.</h3>
Firstly, multiply both sides by b: 
Next, divide both sides by c and <u>your answer will be
</u>