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.

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 3 as well and sum (Inside, Outside) to equal 4. For this problem, those two numbers are 1 and 3. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 4y + 3
y² + (1 + 3)y + (1 x 3)
(y + 1)(y + 3)

An isosceles triangle has two sides of equal length. An equilateral triangle has three sides of equal length. In a right triangle, two sides meet at a right angle.

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 + 7)(y + 9)
(y x y) + (y x 9) + (7 x y) + (7 x 9)
y² + 9y + 7y + 63
y² + 16y + 63

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

v = h x l x w
v = 1 x 7 x 3
v = 21