To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses:

(y - 7)(y - 1)
(y x y) + (y x -1) + (-7 x y) + (-7 x -1)
y² - y - 7y + 7
y² - 8y + 7

An isosceles triangle has two sides of equal length. An equilateral triangle has three sides of equal length. In a right triangle, two sides meet at a right angle.

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.

5a⁹ + 4a⁹ = 9a⁹

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

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

r = \( \frac{d}{2} \)
r = \( \frac{4}{2} \)
r = 2
a = πr²
a = π(2²)
a = 4π