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

sa = 2πr² + 2πrh
sa = 2π(4²) + 2π(4 x 8)
sa = 2π(16) + 2π(32)
sa = (2 x 16)π + (2 x 32)π
sa = 32π + 64π
sa = 96π

The surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):

sa = 2lw + 2wh + 2lh
sa = (2 x 6 x 4) + (2 x 4 x 1) + (2 x 6 x 1)
sa = (48) + (8) + (12)
sa = 68

The Pythagorean theorem defines the relationship between the side lengths of a right triangle. The length of the hypotenuse squared (c²) is equal to the sum of the two perpendicular sides squared (a² + b²): c² = a² + b² or, solved for c, \(c = \sqrt{a + b}\)

You can only add or subtract monomials that have the same variable and the same exponent. For example, 2a + 4a = 6a and 4a² - a² = 3a² but 2a + 4b and 7a - 3b cannot be combined. However, you can multiply and divide monomials with unlike terms. For example, 2a x 6b = 12ab.

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

-9b - 8x = -2b - 5x - 7
-9b = -2b - 5x - 7 + 8x
-9b + 2b = -5x - 7 + 8x
-7b = 3x - 7
b = \( \frac{3x - 7}{-7} \)
b = \( \frac{3x}{-7} \) + \( \frac{-7}{-7} \)
b = -\(\frac{3}{7}\)x + 1