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 circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).

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, \(c = \sqrt{a + b}\)

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:

y² - 10y + 27 = y - 3
y² - 10y + 27 + 3 = y
y² - 10y - y + 30 = 0
y² - 11y + 30 = 0

Next, factor the quadratic equation:

y² - 11y + 30 = 0
(y - 5)(y - 6) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y - 5) or (y - 6) must equal zero:

If (y - 5) = 0, y must equal 5
If (y - 6) = 0, y must equal 6

So the solution is that y = 5 or 6

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 7 + 6 + 2 + 9
p = 24