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 1 x 7) + (2 x 7 x 4) + (2 x 1 x 4)
sa = (14) + (56) + (8)
sa = 78

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 < sign and the answer on the other.

-4c - 8 < \( \frac{c}{3} \)
3 x (-4c - 8) < c
(3 x -4c) + (3 x -8) < c
-12c - 24 < c
-12c - 24 - c < 0
-12c - c < 24
-13c < 24
c < \( \frac{24}{-13} \)
c < -1\(\frac{11}{13}\)

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

sa = 2πr² + 2πrh
sa = 2π(3²) + 2π(3 x 3)
sa = 2π(9) + 2π(9)
sa = (2 x 9)π + (2 x 9)π
sa = 18π + 18π
sa = 36π

The area of a rectangle is equal to its length x width:

a = l x w
a = a x b
a = 5 x 1
a = 5

To factor a quadratic expression, apply the FOIL method (First, Outside, Inside, Last) in reverse. First, find the two Last terms that will multiply to produce 40 as well and sum (Inside, Outside) to equal -13. For this problem, those two numbers are -8 and -5. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - 13y + 40
y² + (-8 - 5)y + (-8 x -5)
(y - 8)(y - 5)