To solve this equation, isolate the variable for which you are solving (b) on one side of the equation and put everything else on the other side.

7b + 9y = -6b - 2y + 1
7b = -6b - 2y + 1 - 9y
7b + 6b = -2y + 1 - 9y
13b = -11y + 1
b = \( \frac{-11y + 1}{13} \)
b = \( \frac{-11y}{13} \) + \( \frac{1}{13} \)
b = -\(\frac{11}{13}\)y + \(\frac{1}{13}\)

To solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)

6a(a - z)
6(-5)(-5 - 7)
6(-5)(-12)
(-30)(-12)
360

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 -12 as well and sum (Inside, Outside) to equal -4. For this problem, those two numbers are -6 and 2. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - 4y - 12
y² + (-6 + 2)y + (-6 x 2)
(y - 6)(y + 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 surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):

sa = 2lw + 2wh + 2lh
sa = (2 x 2 x 9) + (2 x 9 x 9) + (2 x 2 x 9)
sa = (36) + (162) + (36)
sa = 234