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 right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.

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 -6 and 9. Then, plug these into a set of binomials using the square root of the First variable (y²):

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

You need to find the value of c so solve the first equation in terms of x:

6c + x = 9
x = 9 - 6c

then substitute the result (9 - 6c) into the second equation:

-8c - 9(9 - 6c) = -3
-8c + (-9 x 9) + (-9 x -6c) = -3
-8c - 81 + 54c = -3
-8c + 54c = -3 + 81
46c = 78
c = \( \frac{78}{46} \)
c = 1\(\frac{16}{23}\)

A monomial contains one term, a binomial contains two terms, and a polynomial contains more than two terms.