To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

2a - 5a = -3a

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

4a⁹ - 9a⁹ = -5a⁹

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 > sign and the answer on the other.

-b - 9 > \( \frac{b}{5} \)
5 x (-b - 9) > b
(5 x -b) + (5 x -9) > b
-5b - 45 > b
-5b - 45 - b > 0
-5b - b > 45
-6b > 45
b > \( \frac{45}{-6} \)
b > -7\(\frac{1}{2}\)

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 area of a rectangle is equal to its length x width:

a = l x w
a = a x b
a = 7 x 8
a = 56