The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

(7a)(8ab) + (4a²)(5b)
(7 x 8)(a x a x b) + (4 x 5)(a² x b)
(56)(a¹⁺¹ x b) + (20)(a²b)
56a²b + 20a²b
76a²b

A line segment is a portion of a line with a measurable length. The midpoint of a line segment is the point exactly halfway between the endpoints. The midpoint bisects (cuts in half) the line segment.

The formula for circumference is circle diameter x π. Circle diameter is 2 x radius:

c = πd
c = π(2 * r)
c = π(2 * 10)
c = 20π

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

-9z - 2 = -4 + 5z
-9z = -4 + 5z + 2
-9z - 5z = -4 + 2
-14z = -2
z = \( \frac{-2}{-14} \)
z = \(\frac{1}{7}\)