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.

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 42 as well and sum (Inside, Outside) to equal 13. For this problem, those two numbers are 6 and 7. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 13y + 42
y² + (6 + 7)y + (6 x 7)
(y + 6)(y + 7)

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 4 x 1 = \( \frac{4}{2} \) = 2

When solving an equation with two variables, 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.)

The coordinate grid is composed of a horizontal x-axis and a vertical y-axis. The center of the grid, where the x-axis and y-axis meet, is called the origin.