Noah says that to find 20% of a number he divides the number by 5. For example, 20% of 60 is 12, because 60 ÷ 5 = 12. Does Noah’s method always work? Explain why or why not.

What is the value of x in the equation 2(x-4) = 4(2x + 1)?

Find the area of the triangle shown 3 by 6

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?