An acute angle measures less than 90°, a right angle measures 90°, and an obtuse angle measures more than 90°.

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 56 as well and sum (Inside, Outside) to equal -15. For this problem, those two numbers are -8 and -7. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - 15y + 56
y² + (-8 - 7)y + (-8 x -7)
(y - 8)(y - 7)

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.

-7c + 2 > 3 + 2c
-7c > 3 + 2c - 2
-7c - 2c > 3 - 2
-9c > 1
c > \( \frac{1}{-9} \)
c > -\(\frac{1}{9}\)

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.

4a² - 6a² = -2a²

The formula for area is πr². Radius is circle \( \frac{diameter}{2} \):

r = \( \frac{d}{2} \)
r = \( \frac{8}{2} \)
r = 4
a = πr²
a = π(4²)
a = 16π