Instructions: Solve the following system of equations algebraically. If there are no real solutions, type "none" in both blanks. If there is only one, type "none" in the other blank.

[tex]\[
\begin{cases}
y = -2x - 7 \\
y = x^2 + 6x + 8
\end{cases}
\][/tex]



Answer :

To solve the system of equations:
[tex]\[ \left\{\begin{array}{l} y = -2x - 7 \\ y = x^2 + 6x + 8 \end{array}\right. \][/tex]

we need to find the values of [tex]\(x\)[/tex] and [tex]\(y\)[/tex] that satisfy both equations simultaneously.

### Step 1: Set the equations equal to each other

Since both equations are equal to [tex]\(y\)[/tex], we can set them equal to each other:
[tex]\[ -2x - 7 = x^2 + 6x + 8 \][/tex]

### Step 2: Arrange into a standard quadratic equation form

Combine all the terms on one side:
[tex]\[ 0 = x^2 + 6x + 8 + 2x + 7 \][/tex]

Simplify:
[tex]\[ 0 = x^2 + 8x + 15 \][/tex]

### Step 3: Solve the quadratic equation

The quadratic equation to solve is:
[tex]\[ x^2 + 8x + 15 = 0 \][/tex]

We can solve this by factoring. Looking for two numbers that multiply to 15 and add up to 8, we find:
[tex]\[ (x + 3)(x + 5) = 0 \][/tex]

Setting each factor to zero gives us the solutions for [tex]\(x\)[/tex]:
[tex]\[ x + 3 = 0 \quad \Rightarrow \quad x = -3 \][/tex]
[tex]\[ x + 5 = 0 \quad \Rightarrow \quad x = -5 \][/tex]

### Step 4: Find the corresponding [tex]\(y\)[/tex] values

Substitute [tex]\(x = -3\)[/tex] and [tex]\(x = -5\)[/tex] back into either original equation to find the corresponding [tex]\(y\)[/tex] values. We use [tex]\(y = -2x - 7\)[/tex] for simplicity:

For [tex]\(x = -3\)[/tex]:
[tex]\[ y = -2(-3) - 7 = 6 - 7 = -1 \][/tex]

For [tex]\(x = -5\)[/tex]:
[tex]\[ y = -2(-5) - 7 = 10 - 7 = 3 \][/tex]

### Conclusion

The solutions to the system of equations are:
[tex]\[ (x, y) = (-3, -1) \quad \text{and} \quad (x, y) = (-5, 3) \][/tex]

Therefore, the points of intersection are:
[tex]\[ \boxed{(-5, 3)} \quad \text{and} \quad \boxed{(-3, -1)} \][/tex]