Answer:
y = x² − 6x − 27
Step-by-step explanation:
To distribute, you can use something called FOIL. It stands for First, Outer, Inner, Last.
First, multiply the First term in each factor.
x · x = x²
Now multiply the Outer terms in each factor.
x · 3 = 3x
Next multiply the Inner terms in each factor.
-9 · x = -9x
Finally, multiply the Last terms in each factor.
-9 · 3 = -27
Add them all up:
x² + 3x − 9x − 27
x² − 6x − 27
Answer:
<em>(a) x=2, y=-1</em>
<em>(b) x=2, y=2</em>
<em>(c)</em> 
<em>(d) x=-2, y=-7</em>
Step-by-step explanation:
<u>Cramer's Rule</u>
It's a predetermined sequence of steps to solve a system of equations. It's a preferred technique to be implemented in automatic digital solutions because it's easy to structure and generalize.
It uses the concept of determinants, as explained below. Suppose we have a 2x2 system of equations like:

We call the determinant of the system

We also define:

And

The solution for x and y is


(a) The system to solve is

Calculating:





The solution is x=2, y=-1
(b) The system to solve is

Calculating:





The solution is x=2, y=2
(c) The system to solve is

Calculating:





The solution is

(d) The system to solve is

Calculating:





The solution is x=-2, y=-7