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

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(8 + 3)(3)
a = ½(11)(3)
a = ½(33) = \( \frac{33}{2} \)
a = 16\(\frac{1}{2}\)

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

7a - 9a = -2a

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.

9y - 5 = 2 + 3y
9y = 2 + 3y + 5
9y - 3y = 2 + 5
6y = 7
y = \( \frac{7}{6} \)
y = 1\(\frac{1}{6}\)

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.

5a x 5b = (5 x 5) (a x b) = 25ab