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 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.

(4a)(4ab) + (8a²)(2b)
(4 x 4)(a x a x b) + (8 x 2)(a² x b)
(16)(a¹⁺¹ x b) + (16)(a²b)
16a²b + 16a²b
32a²b

A cylinder is a solid figure with straight parallel sides and a circular or oval cross section with a radius (r) and a height (h). The volume of a cylinder is π r²h and the surface area is 2(π r²) + 2π rh.

The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

x² - 7x + 16 = x + 1
x² - 7x + 16 - 1 = x
x² - 7x - x + 15 = 0
x² - 8x + 15 = 0

Next, factor the quadratic equation:

x² - 8x + 15 = 0
(x - 3)(x - 5) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (x - 3) or (x - 5) must equal zero:

If (x - 3) = 0, x must equal 3
If (x - 5) = 0, x must equal 5

So the solution is that x = 3 or 5