I need step by step help on solving this equation:

4x^2 - 15x = 3

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- Sep 1st 2010, 04:34 PMjenbonesHow to solve this equation
I need step by step help on solving this equation:

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

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

by the quadartic formula

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

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

You got it from here? - Sep 1st 2010, 05:10 PMjenbones
- Sep 1st 2010, 05:24 PMfireballs619
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 PMjenbones