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:

z² + 5z - 39 = 2z + 1
z² + 5z - 39 - 1 = 2z
z² + 5z - 2z - 40 = 0
z² + 3z - 40 = 0

Next, factor the quadratic equation:

z² + 3z - 40 = 0
(z - 5)(z + 8) = 0

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

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

So the solution is that z = 5 or -8

The coordinate grid is composed of a horizontal x-axis and a vertical y-axis. The center of the grid, where the x-axis and y-axis meet, is called the origin.

The formula for area is πr²:

a = πr²
a = π(2²)
a = 4π

To factor a quadratic expression, apply the FOIL (First, Outside, Inside, Last) method in reverse.