Given the system of equations:
[tex]\[ y = x^2 + 8x - 33 \][/tex]
[tex]\[ y = 2x - 6 \][/tex]

What is the greatest possible value of [tex]\( x \)[/tex] for which there is some solution [tex]\((x, y)\)[/tex] to the given system of equations?



Answer :

To solve for the greatest possible value of [tex]\( x \)[/tex] where there is some solution [tex]\( (x, y) \)[/tex] to the given system of equations, we will follow these steps:

1. Write the system of equations:
[tex]\[ \begin{cases} y = x^2 + 8x - 33 \\ y = 2x - 6 \end{cases} \][/tex]

2. Set the equations equal to each other:
Since both expressions equal [tex]\( y \)[/tex], we can set the right-hand sides of these equations equal to each other:
[tex]\[ x^2 + 8x - 33 = 2x - 6 \][/tex]

3. Rearrange the equation:
Get all terms on one side to form a standard quadratic equation:
[tex]\[ x^2 + 8x - 33 - 2x + 6 = 0 \][/tex]
Simplify by combining like terms:
[tex]\[ x^2 + 6x - 27 = 0 \][/tex]

4. Solve the quadratic equation:
We can solve the quadratic equation [tex]\( x^2 + 6x - 27 = 0 \)[/tex] using the quadratic formula [tex]\( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \)[/tex], where [tex]\( a = 1 \)[/tex], [tex]\( b = 6 \)[/tex], and [tex]\( c = -27 \)[/tex]:
[tex]\[ x = \frac{-6 \pm \sqrt{6^2 - 4 \cdot 1 \cdot (-27)}}{2 \cdot 1} \][/tex]
[tex]\[ x = \frac{-6 \pm \sqrt{36 + 108}}{2} \][/tex]
[tex]\[ x = \frac{-6 \pm \sqrt{144}}{2} \][/tex]
[tex]\[ x = \frac{-6 \pm 12}{2} \][/tex]
This yields two solutions:
[tex]\[ x = \frac{-6 + 12}{2} = \frac{6}{2} = 3 \][/tex]
and
[tex]\[ x = \frac{-6 - 12}{2} = \frac{-18}{2} = -9 \][/tex]

5. Identify the greatest [tex]\( x \)[/tex] value:
The solutions for [tex]\( x \)[/tex] are [tex]\( 3 \)[/tex] and [tex]\( -9 \)[/tex]. The greatest possible value of [tex]\( x \)[/tex] is therefore:
[tex]\[ \boxed{3} \][/tex]