To solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)

6a(a - x)
6(-1)(-1 + 6)
6(-1)(5)
(-6)(5)
-30

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 8 as well and sum (Inside, Outside) to equal 6. For this problem, those two numbers are 2 and 4. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 6y + 8
y² + (2 + 4)y + (2 x 4)
(y + 2)(y + 4)

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

p = x + y + z
p = 5cm + 8cm + 8cm = 21cm

The slope-intercept equation for a line is y = mx + b where m is the slope and b is the y-intercept of the line. From the graph, you can see that the y-intercept (the y-value from the point where the line crosses the y-axis) is -1. The slope of this line is the change in y divided by the change in x. The endpoints of this line segment are at (-2, 5) and (2, -7) so the slope becomes:

Plugging these values into the slope-intercept equation:

y = -3x - 1

The volume of a cube is height x length x width:

v = h x l x w
v = 8 x 1 x 2
v = 16