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 -7 and -6. Then, plug these into a set of binomials using the square root of the First variable (y²):

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

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.

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.)

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.

-2c - 1 < -7 - 3c
-2c < -7 - 3c + 1
-2c + 3c < -7 + 1
c < -6

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses.