You can only add or subtract monomials that have the same variable and the same exponent. For example, 2a + 4a = 6a and 4a² - a² = 3a² but 2a + 4b and 7a - 3b cannot be combined. However, you can multiply and divide monomials with unlike terms. For example, 2a x 6b = 12ab.

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

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:

b² - 12b + 13 = -4b - 2
b² - 12b + 13 + 2 = -4b
b² - 12b + 4b + 15 = 0
b² - 8b + 15 = 0

Next, factor the quadratic equation:

b² - 8b + 15 = 0
(b - 3)(b - 5) = 0

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

If (b - 3) = 0, b must equal 3
If (b - 5) = 0, b must equal 5

So the solution is that b = 3 or 5

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:

(y - 6)(y + 5)
(y x y) + (y x 5) + (-6 x y) + (-6 x 5)
y² + 5y - 6y - 30
y² - y - 30

The Pythagorean theorem defines the relationship between the side lengths of a right triangle. The length of the hypotenuse squared (c²) is equal to the sum of the two perpendicular sides squared (a² + b²): c² = a² + b² or, solved for c, \(c = \sqrt{a + b}\)