Monday, November 2, 2015

Solve the equation: | 3x^2 – 9x + 4| = 14

l 3x^2 - 9x +4 l = 14


We have
two cases:


Case(1);


3x^2 - 9x
+ 4 = 14


==> 3x^2 - 9x +4 -14 =
0


==> 3x^2 - 9x -10 =
0


Now we will use the quadratic equation to solve for
x.


==> x1 = ( 9 + sqrt(81+4*3*10) /
6


             = ( 9 + sqrt(201) /
6


  ==> x1= ( 3/2) + sqrt(210) /
6


==> x2= (3/2) -
sqrt(210) /
6


 


Case(2).


==>
-(3x^2 -9x +4 ) = 14


==> -3x^2 + 9x -4 =
14


==> -3x^2 + 9x -18 =
0


==> x1= ( -9 + sqrt(81-4*3*18) /
-6


            = ( -9 + sqrt(135)*i ) /
-6


              = ( 3/2) + 3sqrt(15) i
/6


             = (3/2) + (sqrt15 /2
)*i


==> x1= (3/2) + (sqrt15 / 2)
*i


==> x2 = (3/2) -
9sqrt15 /2)*i

No comments:

Post a Comment

Calculate tan(x-y), if sin x=1/2 and sin y=1/3. 0

We'll write the formula of the tangent of difference of 2 angles. tan (x-y) = (tan x - tan y)/(1 + tan x*tan y) ...