To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

6a + 9 = -6 - 3a
6a = -6 - 3a - 9
6a + 3a = -6 - 9
9a = -15
a = \( \frac{-15}{9} \)
a = -1\(\frac{2}{3}\)

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 -5 as well and sum (Inside, Outside) to equal -4. For this problem, those two numbers are -5 and 1. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - 4y - 5
y² + (-5 + 1)y + (-5 x 1)
(y - 5)(y + 1)

A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).

The entire length of this line is represented by AD which is AB + BD:

AD = AB + BD

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).