A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

7a⁷ + 5a⁷ = 12a⁷

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 -54 as well and sum (Inside, Outside) to equal -3. For this problem, those two numbers are -9 and 6. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - 3y - 54
y² + (-9 + 6)y + (-9 x 6)
(y - 9)(y + 6)

A cylinder is a solid figure with straight parallel sides and a circular or oval cross section with a radius (r) and a height (h). The volume of a cylinder is π r²h and the surface area is 2(π r²) + 2π rh.

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

v = h x l x w
v = 3 x 5 x 8
v = 120