1. ## quadratic equation

Hi,

how can I solve a quadratic equation where a is not equal to one.
ex:
$2y^2 +y-1=0$

P.s: I want the fastest method

2. Originally Posted by Musab
Hi,

how can I solve a quadratic equation where a is not equal to one.
ex:
$2y^2 +y-1=0$

P.s: I want the fastest method

In this case You can factor my dear friend...

$2y^2+y-1=(2y-?)(y+?)$

3. Originally Posted by VonNemo19
In this case You can factor my dear friend...

$2y^2+y-1=(2y-?)(y+?)$

so, it does not matter which number goes with the 2y and which goes with the y ?

4. Originally Posted by Musab
so, it does not matter which number goes with the 2y and which goes with the y ?
Sure it does. What numbers should I use so that

Remember, when factoring, the thing still has to preserve equality. You know how to foil right? You've got to do the reverse process here. It takes some practice, but one you get good at it, your life will be much easier.

Try this. Let the question marks be equal to 1. Multiply it out to verify that you have factored correctly. Then, ask yourself, what values of y will make $(2y-1)(y+1)=0$