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

7c + 4y = -8c + y + 4
7c = -8c + y + 4 - 4y
7c + 8c = y + 4 - 4y
15c = -3y + 4
c = \( \frac{-3y + 4}{15} \)
c = \( \frac{-3y}{15} \) + \( \frac{4}{15} \)
c = -\(\frac{1}{5}\)y + \(\frac{4}{15}\)

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.

-x - 5 > 6 + x
-x > 6 + x + 5
-x - x > 6 + 5
-2x > 11
x > \( \frac{11}{-2} \)
x > -5\(\frac{1}{2}\)

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

A rhombus is a parallelogram with four equal-length sides. A square is a rectangle with four equal-length sides.

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 20 as well and sum (Inside, Outside) to equal -9. For this problem, those two numbers are -5 and -4. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - 9y + 20
y² + (-5 - 4)y + (-5 x -4)
(y - 5)(y - 4)