Solving Systems

Instructions: Solve the following systems 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]\[
\begin{cases}
y = -\frac{1}{3}x - 6 \\
y = x^2 + 6x + 5
\end{cases}
\][/tex]

( [tex]$\square$[/tex] , [tex]$\square$[/tex] ) ( [tex]$\square$[/tex] , [tex]$\square$[/tex] )



Answer :

To solve the system of equations algebraically, we need to find the points of intersection of the two equations:

[tex]\[ \left\{\begin{array}{l} y=-\frac{1}{3} x-6 \\ y=x^2+6x+5 \end{array}\right. \][/tex]

1. Set the equations equal to each other to determine the values of [tex]\(x\)[/tex], since at the points of intersection the [tex]\(y\)[/tex]-values are the same for both equations:

[tex]\[ -\frac{1}{3} x - 6 = x^2 + 6x + 5 \][/tex]

2. Clear the fraction by multiplying every term by 3:

[tex]\[ - x - 18 = 3x^2 + 18x + 15 \][/tex]

3. Rearrange the equation to set it to zero:

[tex]\[ 3x^2 + 18x + 15 + x + 18 = 0 \][/tex]

[tex]\[ 3x^2 + 19x + 33 = 0 \][/tex]

4. Solve the quadratic equation [tex]\( 3x^2 + 19x + 33 = 0 \)[/tex]. To solve for [tex]\(x\)[/tex], we use the quadratic formula:

[tex]\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \][/tex]

where [tex]\(a = 3\)[/tex], [tex]\(b = 19\)[/tex], and [tex]\(c = 33\)[/tex].

5. Calculate the discriminant ([tex]\(\Delta\)[/tex]):

[tex]\[ \Delta = b^2 - 4ac = 19^2 - 4 \cdot 3 \cdot 33 = 361 - 396 = -35 \][/tex]

Since the discriminant is negative, there are no real solutions for [tex]\(x\)[/tex].

6. Because there are no real solutions for [tex]\(x\)[/tex], the system has no points of intersection.

There are no real solutions to this system of equations. Therefore, the correct answer is:

( None, None ), ( None, None )