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 -72 as well and sum (Inside, Outside) to equal -1. For this problem, those two numbers are -9 and 8. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - y - 72
y² + (-9 + 8)y + (-9 x 8)
(y - 9)(y + 8)

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 + 2a = 9a

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.

A cube is a rectangular solid box with a height (h), length (l), and width (w). The volume is h x l x w and the surface area is 2lw x 2wh + 2lh.

You need to find the value of a so solve the first equation in terms of y:

-a + y = -2
y = -2 + a

then substitute the result (-2 - -1a) into the second equation:

-5a + 2(-2 + a) = -3
-5a + (2 x -2) + (2 x a) = -3
-5a - 4 + 2a = -3
-5a + 2a = -3 + 4
-3a = 1
a = \( \frac{1}{-3} \)
a = -\(\frac{1}{3}\)