A cube is a rectangular solid box with a height (h), length (l), and width (w). The volume is h x l x w and the surface area is 2lw x 2wh + 2lh.

The perimeter of a triangle is the sum of the lengths of its sides:

p = x + y + z
p = 9cm + 13cm + 15cm = 37cm

The entire length of this line is represented by AD which is AB + BD:

AD = AB + BD

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 -24 as well and sum (Inside, Outside) to equal 5. For this problem, those two numbers are -3 and 8. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 5y - 24
y² + (-3 + 8)y + (-3 x 8)
(y - 3)(y + 8)

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 8 x 6) + (2 x 6 x 1) + (2 x 8 x 1)
sa = (96) + (12) + (16)
sa = 124