A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).

According to the Pythagorean theorem, the hypotenuse squared is equal to the sum of the two perpendicular sides squared:

c² = a² + b²
c² = 2² + 3²
c² = 4 + 9
c² = 13
c = \( \sqrt{13} \)

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.

(6a)(9ab) + (6a²)(4b)
(6 x 9)(a x a x b) + (6 x 4)(a² x b)
(54)(a¹⁺¹ x b) + (24)(a²b)
54a²b + 24a²b
78a²b

A rhombus is a parallelogram with four equal-length sides. A square is a rectangle with four equal-length sides.

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.

-7a + 5 = -7 - 2a
-7a = -7 - 2a - 5
-7a + 2a = -7 - 5
-5a = -12
a = \( \frac{-12}{-5} \)
a = 2\(\frac{2}{5}\)