Question

Please help!? 5 Stars! :0 :(

Answer 1

OK.  These problems are easy if you know the quadratic formula,
and they're impossible if you don't.

Here's the quadratic formula:

When the equation is in the form of      Ax² + Bx + C = 0

then                    x =  [ -B plus or minus √(B²-4AC) ] / 2A

I'm sure that formula is in your text or your study notes,
right before these questions.  You should cut it out or
copy it, and tape it inside the cover of your notebook.
Then, you'll always have it when you need it, until
you have it memorized and can rattle it off.

The first question says        3x²  +  5x  +  2  = 0

Is this in the form of             Ax²  +  Bx  +  C  = 0    ?

             Yes !                    A=3      B=5   C=2

             so you can use the quadratic formula to solve it.

            x =  [ -B plus or minus √(B²-4AC) ] / 2A

               =  [ -5 plus or minus √(5² - 4·3·2) ] / 2·3

               =  [ -5 plus or minus √(25 - 24)  ]  /  6

               =  [  -5 plus or minus  √1          ]  /  6

           x  =        -4 / 6  =  -2/3
and
           x  =        -6 / 6  =  -1 .    
_______________________________________

The second question says

                                         4x²  +  5x  -  1 = 0

Is this in the form of          Ax²  +  Bx + C = 0  ?

           Yes it is !            A=4     B=5   C= -1  

         so you can use the quadratic formula to solve it.

            x =  [ -B plus or minus √(B²-4AC) ] / 2A

Now, you take it from here.