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).

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)(2ab) - (2a²)(2b)
(2 x 2)(a x a x b) - (2 x 2)(a² x b)
(4)(a¹⁺¹ x b) - (4)(a²b)
4a²b - 4a²b
0a²b

The sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 49° - 37° = 94°

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 > sign and the answer on the other.

-x + 2 > -7 - 8x
-x > -7 - 8x - 2
-x + 8x > -7 - 2
7x > -9
x > \( \frac{-9}{7} \)
x > -1\(\frac{2}{7}\)

The surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):

sa = 2lw + 2wh + 2lh
sa = (2 x 6 x 7) + (2 x 7 x 7) + (2 x 6 x 7)
sa = (84) + (98) + (84)
sa = 266