fator the expression -40x^2 - 47x- 12

Question

how do I factor the expression

Answer 1

-40x^2 - 47x- 12  

 

You will notice each term has negative sign.  So, take the negative sign out:

 

-(40x2 + 47x +12)  =  - (8x+3) (5x+4).  How did I get it? try and error.

 

If you want to get the answer right away, quadratic formula will do the trick (just like Dorene did).

 

Good Luck.

Answer 2

you use the quadratic formula, the two solutions are   -b+/-  sqrt(b² -4ac)

                                                                                          2a

 

so 47 +/- sqrt(2209 - 1920)      =     47 +/- 17        =    30/80 = -3/8 and 64/80 = -4/5

                 - 80                                    - 80

 

the two factors will be (x+3/8)(x+4/5)

 

main thing is making sure all your factors are correct and you keep track of the minus signs

 

Dorene O.