A. <span>–13 + 27 = 27 + (–13) is an example of the commutative property.
The commutative property states that a + b = b + a.</span>
X + y = 2 —> y = 2 - x
insert to first equation
2-x=x^2-3x-6
x^2 - 3x - 6 - 2 + x = 0
x^2 - 2x - 8 = 0
(x-4)(x+2) = 0
x = 4 or x = -2
Un answerable how many friends buy tickets?
Mmm looks like a test. I don't know if we should be answering this.