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 4 as well and sum (Inside, Outside) to equal -4. For this problem, those two numbers are -2 and -2. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - 4y + 4
y² + (-2 - 2)y + (-2 x -2)
(y - 2)(y - 2)

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

-4c + x = -8
x = -8 + 4c

then substitute the result (-8 - -4c) into the second equation:

c - 8(-8 + 4c) = -2
c + (-8 x -8) + (-8 x 4c) = -2
c + 64 - 32c = -2
c - 32c = -2 - 64
-31c = -66
c = \( \frac{-66}{-31} \)
c = 2\(\frac{4}{31}\)

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.

The formula for area is πr². Radius is circle \( \frac{diameter}{2} \):

r = \( \frac{d}{2} \)
r = \( \frac{8}{2} \)
r = 4
a = πr²
a = π(4²)
a = 16π

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.