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 4 x 5) + (2 x 5 x 7) + (2 x 4 x 7)
sa = (40) + (70) + (56)
sa = 166

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 sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 60° - 28° = 92°

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:

x² + 4x + 10 = -4x - 5
x² + 4x + 10 + 5 = -4x
x² + 4x + 4x + 15 = 0
x² + 8x + 15 = 0

Next, factor the quadratic equation:

x² + 8x + 15 = 0
(x + 3)(x + 5) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (x + 3) or (x + 5) must equal zero:

If (x + 3) = 0, x must equal -3
If (x + 5) = 0, x must equal -5

So the solution is that x = -3 or -5

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

(2a)(3ab) + (7a²)(9b)
(2 x 3)(a x a x b) + (7 x 9)(a² x b)
(6)(a¹⁺¹ x b) + (63)(a²b)
6a²b + 63a²b
69a²b