SOLUTION: Solve this quadratic equation using the Difference of Two Squares rule: 8x^2-2=0 Solve this quadratic equation using the "multiply to give, add to give" rule: 3x^2-5x-12=0 Th

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Solve this quadratic equation using the Difference of Two Squares rule: 8x^2-2=0 Solve this quadratic equation using the "multiply to give, add to give" rule: 3x^2-5x-12=0 Th      Log On


   



Question 225245: Solve this quadratic equation using the Difference of Two Squares rule:
8x^2-2=0
Solve this quadratic equation using the "multiply to give, add to give" rule:
3x^2-5x-12=0
Thanks

Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!

Solve this quadratic equation using the "multiply to give, add to give" rule:

3x^2-5x-12=0

Thanks
Answer by Edwin McCravy(2810) About Me  (Show Source):

You can put this solution on YOUR website!



Divide every term by 2









2x - 1 = 0      2x + 1 = 0
    2x = 1          2x = -1
     x =           x = 

-----------------------------------------------------------



Multiply  by , get 

Think of two numbers that multiply to 
give you  and add to give you .

Answer:  and 

So use those numbers  and 

to write the middle term  as 

So



now becomes:



Now out of the first two terms on the left 
factor out 



Out of the last two terms on the left 
factor out 



Notice that  occurs in
both terms on the left:



So factor out 



 x - 3 = 0      3x + 4 = 0
     x = 3          3x = -4
                     x =
Edwin