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.

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

9a - 3a = 6a

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

x² - x - 56 = 0
(x + 7)(x - 8) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (x + 7) or (x - 8) must equal zero:

If (x + 7) = 0, x must equal -7
If (x - 8) = 0, x must equal 8

So the solution is that x = -7 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.

According to the Pythagorean theorem, the hypotenuse squared is equal to the sum of the two perpendicular sides squared:

c² = a² + b²
c² = 4² + 9²
c² = 16 + 81
c² = 97
c = \( \sqrt{97} \)