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 8 as well and sum (Inside, Outside) to equal 9. For this problem, those two numbers are 1 and 8. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 9y + 8
y² + (1 + 8)y + (1 x 8)
(y + 1)(y + 8)

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 solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

-a + 2 = \( \frac{a}{9} \)
9 x (-a + 2) = a
(9 x -a) + (9 x 2) = a
-9a + 18 = a
-9a + 18 - a = 0
-9a - a = -18
-10a = -18
a = \( \frac{-18}{-10} \)
a = 1\(\frac{4}{5}\)

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.

7a + 4a = 11a

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 5 x 1 = \( \frac{5}{2} \) = 2\(\frac{1}{2}\)