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

c² + 3c - 40 = 0
(c - 5)(c + 8) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (c - 5) or (c + 8) must equal zero:

If (c - 5) = 0, c must equal 5
If (c + 8) = 0, c must equal -8

So the solution is that c = 5 or -8

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).

To solve this equation, isolate the variable for which you are solving (a) on one side of the equation and put everything else on the other side.

3a + z = 2a - 2z - 3
3a = 2a - 2z - 3 - z
3a - 2a = -2z - 3 - z
a = -3z - 3

An isosceles triangle has two sides of equal length. An equilateral triangle has three sides of equal length. In a right triangle, two sides meet at a right angle.

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.

-7c - 7 = \( \frac{c}{9} \)
9 x (-7c - 7) = c
(9 x -7c) + (9 x -7) = c
-63c - 63 = c
-63c - 63 - c = 0
-63c - c = 63
-64c = 63
c = \( \frac{63}{-64} \)
c = -\(\frac{63}{64}\)