Answer:
x = 8
Step-by-step explanation:
An Equilateral triangle is a triangle in which all three sides and angles are equal. The value of each angle of an equilateral triangle is 60 degrees therefore we get the equation 9x - 12 = 60
Add 12 from both sides to isolate the 9x leaving us with:
9x = 72
Divide both sides by 9 to give us x, which is
x = 8
