# How to solve this equation

• Sep 1st 2010, 04:34 PM
jenbones
How to solve this equation
I need step by step help on solving this equation:

4x^2 - 15x = 3
• Sep 1st 2010, 04:41 PM
pickslides
$\displaystyle \displaystyle 4x^2 - 15x = 3$

$\displaystyle \displaystyle 4x^2 - 15x -3= 0$

$\displaystyle \displaystyle ax^2 + bx +c= 0 \implies x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}$

$\displaystyle \displaystyle 4x^2 - 15x -3= 0 \implies x = \frac{-(-15)\pm\sqrt{(-15)^2-4\times 4\times (-3)}}{2\times 4}$

You got it from here?
• Sep 1st 2010, 05:10 PM
jenbones
Quote:

Originally Posted by pickslides
$\displaystyle \displaystyle 4x^2 - 15x = 3$

$\displaystyle \displaystyle 4x^2 - 15x -3= 0$

$\displaystyle \displaystyle ax^2 + bx +c= 0 \implies x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}$

$\displaystyle \displaystyle 4x^2 - 15x -3= 0 \implies x = \frac{-(-15)\pm\sqrt{(-15)^2-4\times 4\times (-3)}}{2\times 4}$

You got it from here?

I'm confused on what to do next ...
• Sep 1st 2010, 05:24 PM
fireballs619
given the quadratic formula with all variables filled in, you simply simplify down (notice the pun there)

$\displaystyle x = \frac{-(-15)\pm\sqrt{(-15)^2-4\times 4\times (-3)}}{2\times 4}$

$\displaystyle x = \frac{15\pm\sqrt{225-48}}{8}$

$\displaystyle x = \frac{15\pm\sqrt{177}}{8}$

Using order of operations, of course.
• Sep 1st 2010, 07:40 PM
jenbones
Quote:

Originally Posted by fireballs619
given the quadratic formula with all variables filled in, you simply simplify down (notice the pun there)

$\displaystyle x = \frac{-(-15)\pm\sqrt{(-15)^2-4\times 4\times (-3)}}{2\times 4}$

$\displaystyle x = \frac{15\pm\sqrt{225-48}}{8}$

$\displaystyle x = \frac{15\pm\sqrt{177}}{8}$

Using order of operations, of course.

thanks!