Urgent Help with Maths please!!!!?

Question

Hi :D

I've got to complete these questions in the next 20minutes.... Please could you help me with them....
(2)= Square
1. 3x(2) -5x-12=0

2.3x(2)+13x+12=0

3.9x(2)-42x+40=0


Please help 

thanks

Tom

Anonymous · Answer

These are quadratics. I'll do one for you and leave you to do the others.
3x^2 - 5x - 12 = 0
Use standard formula.
x = [5 +-sqrt(25 + 144)] / 6
x = [5 +- 13] / 6
x = 3  and  x = - 4/3.

solutions are  x = 3  and  x = -4/3

You do the rest.  Use quadratic formula (unless you can spot the factors)

Enn · Answer

1) x = -4/3 or x = 3
2) x = -4/3 or x = -3
3) x = 4/3 or x = 10/3

Sam-J · Answer

1.) delta = b^2 - 4ac
             = (-5)^2 - 4(3)(-12)
             = 25 + 144
             = 169

X = [-b +- sqrt(delta) ] / 2a
  = (5 +- 13) / 6

So X1 = 18/6 = 3
     X2 = -8/6 = -4/3

2.) delta = b^2 - 4ac
             = 13^2 - 4(3)(12)
             = 169 - 144
             = 25

X = [-b +- sqrt(delta) ] / 2a
   = (-13 +- 5) / 6

So X1 = -8/6 = -4/3
     X2 = -18/6 = -3

3.) Similarly, delta = b^2 - 4ac
                           = (-42)^2 - 4(9)(40)
                           = 1764 - 1440
                           = 324
 
X = [-b +- sqrt(delta) ] / 2a
   = (42 +- 18) / 18
  
So X1 = 60/18 = 10/3
     X2 = 24/18 = 4/3

Regards,
Sami

Vijay Senapathi · Answer

1.roots -4/3 3
2.roots -3,-4/3

Anonymous · Answer

(3x +4 )(x -3  ) =0

(3x  +4  )( x  + 3 ) = 0

(3x  - 4)(3x-10) = 0

Urgent Help with Maths please!!!!?

5 Answers