quadratic formula

**kelsikels** · June 2nd 2010, 02:23 PM

3x(x-3)= -4

Help!
Thanks

**pickslides** · June 2nd 2010, 02:25 PM

$3x(x-3)= -4$

$3x^2-9x= -4$

$3x^2-9x+4= 0$

$a=3,b=-9,c=4$

Was that o.k?

**Plato** · June 2nd 2010, 02:26 PM

Originally Posted by kelsikels

3x(x-3)= -4

$3x^2-9x+4=0???????$

**kelsikels** · June 2nd 2010, 02:31 PM

what about the second part?

**Plato** · June 2nd 2010, 02:35 PM

Originally Posted by kelsikels

what about the second part?

What second part?
Do you mean the complete solution?
Oh no! That is your job!

**e^(i*pi)** · June 2nd 2010, 02:38 PM

Originally Posted by kelsikels

what about the second part?

The formula is $x = \frac{-b \pm \sqrt{b^2-4ac}}{2a}$

Pickslides has given you values for a, b and c

**pickslides** · June 2nd 2010, 02:40 PM

Originally Posted by pickslides

$a=3,b=-9,c=4$

Substitute these values into

$x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}$

**bigwave** · June 2nd 2010, 03:01 PM

here's a graph of $3x^2-9x+4= 0$ if it is of any interest
the x intercepts are not as obvious as they look.
as mentioned already the quadradic equation will give the intercepts

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