Quadratic Equation Solution Set

**adkinsjr** · September 3rd 2009, 08:11 PM

I'm working on basic problems to review for a placement test into calculus. The questions are here, I don't need you to click on if your not interest, they are multiple choice. College Algebra

Where am I going wrong here?
$x^2-2x-24=24$
$x^2-2x-48=0$
$x=\frac{-(-2)\pm\sqrt{(-2)^2-4(-48)(1)}}{2}=\frac{2\pm\sqrt{4+182}}{2}=\frac{2\pm\ sqrt{186}}{2}$

The solution sets (in the multiple coice) are all whole numbers. I have $\pm\frac{\sqrt{186}}{2}\approx6.819$

Where am I going wrong here?

**Rapha** · September 3rd 2009, 08:25 PM

Hi adkinsjr!

Originally Posted by adkinsjr

I'm working on basic problems to review for a placement test into calculus. The questions are here, I don't need you to click on if your not interest, they are multiple choice. College Algebra

Where am I going wrong here?
$x^2-2x-24=24$
$x^2-2x-48=0$
$x=\frac{-(-2)\pm\sqrt{(-2)^2-4(-48)(1)}}{2}=\frac{2\pm\sqrt{4+182}}{2}=\frac{2\pm\ sqrt{186}}{2}$

The solution sets (in the multiple coice) are all whole numbers. I have $\pm\frac{\sqrt{186}}{2}\approx6.819$

Where am I going wrong here?

This is because 4*48 = 192 not 182

Yours
Rapha

**HallsofIvy** · September 4th 2009, 04:25 AM

You might also have noted that 6(8)= 48 and 8- 6= 2. That is, $x^2- 2x- 48$ factors as $(x- 8)(x+ 6)$ .

Thread: Quadratic Equation Solution Set

LinkBack

Thread Tools

Display

Quadratic Equation Solution Set

Similar Math Help Forum Discussions

solution to f(x) = (f^(-1))(x) using quadratic equation

Probability of a quadratic equation to have a solution

Finding the Solution in a Quadratic Equation?

quadratic solution

solution of the quadratic equation

Search Tags