Answer:
b
Step-by-step explanation:
21 - 4x = 108
<em><u>Subtract 21 from both sides</u></em>
-4x = 87
<em><u>Divide both sides by -4</u></em>
x = -21.75
4.8 or 4 4/5
9,12,18 is a right triangle and so is 30,72,90
