The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

c² - 1 = 0
(c - 1)(c + 1) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (c - 1) or (c + 1) must equal zero:

If (c - 1) = 0, c must equal 1
If (c + 1) = 0, c must equal -1

So the solution is that c = 1 or -1

The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 7 x 5 = \( \frac{35}{2} \) = 17\(\frac{1}{2}\)

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).

The surface area of a cylinder is 2πr² + 2πrh:

sa = 2πr² + 2πrh
sa = 2π(1²) + 2π(1 x 9)
sa = 2π(1) + 2π(9)
sa = (2 x 1)π + (2 x 9)π
sa = 2π + 18π
sa = 20π