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.

(7a)(5ab) - (9a²)(4b)
(7 x 5)(a x a x b) - (9 x 4)(a² x b)
(35)(a¹⁺¹ x b) - (36)(a²b)
35a²b - 36a²b
-1a²b

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).

A trapezoid is a quadrilateral with one set of parallel 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(5 + 9)(5)
a = ½(14)(5)
a = ½(70) = \( \frac{70}{2} \)
a = 35

The volume of a cylinder is πr²h:

v = πr²h
v = π(2² x 6)
v = 24π