The formula for circumference is circle diameter x π:

c = πd
c = 12π

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.

-2b + 9 = 3 + 3b
-2b = 3 + 3b - 9
-2b - 3b = 3 - 9
-5b = -6
b = \( \frac{-6}{-5} \)
b = 1\(\frac{1}{5}\)

You need to find the value of c so solve the first equation in terms of x:

9c + x = -6
x = -6 - 9c

then substitute the result (-6 - 9c) into the second equation:

c - 7(-6 - 9c) = -4
c + (-7 x -6) + (-7 x -9c) = -4
c + 42 + 63c = -4
c + 63c = -4 - 42
64c = -46
c = \( \frac{-46}{64} \)
c = -\(\frac{23}{32}\)

A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses:

(y + 7)(y - 5)
(y x y) + (y x -5) + (7 x y) + (7 x -5)
y² - 5y + 7y - 35
y² + 2y - 35