A parallelogram is a quadrilateral with two sets of parallel sides. Opposite sides (a = c, b = d) and angles (red = red, blue = blue) are equal. The area of a parallelogram is base x height and the perimeter is the sum of the lengths of all sides (a + b + c + d).

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.

(2a)(7ab) - (5a²)(4b)
(2 x 7)(a x a x b) - (5 x 4)(a² x b)
(14)(a¹⁺¹ x b) - (20)(a²b)
14a²b - 20a²b
-6a²b

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 2 + 7 + 9 + 7
p = 25

To solve this equation, isolate the variable for which you are solving (a) on one side of the equation and put everything else on the other side.

7a + 5z = -a + z + 6
7a = -a + z + 6 - 5z
7a + a = z + 6 - 5z
8a = -4z + 6
a = \( \frac{-4z + 6}{8} \)
a = \( \frac{-4z}{8} \) + \( \frac{6}{8} \)
a = -\(\frac{1}{2}\)z + \(\frac{3}{4}\)

A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).