Solve `:x^(2)-59(29)/(30)x-2=0
Answers
Solving 30x2+29x-1830 = 0 by Completing The Square .
Divide both sides of the equation by 30 to have 1 as the coefficient of the first term :
x2+(29/30)x-61 = 0
Add 61 to both side of the equation :
x2+(29/30)x = 61
Now the clever bit: Take the coefficient of x , which is 29/30 , divide by two, giving 29/60 , and finally square it giving 841/3600
Add 841/3600 to both sides of the equation :
On the right hand side we have :
61 + 841/3600 or, (61/1)+(841/3600)
The common denominator of the two fractions is 3600 Adding (219600/3600)+(841/3600) gives 220441/3600
So adding to both sides we finally get :
x2+(29/30)x+(841/3600) = 220441/3600
Adding 841/3600 has completed the left hand side into a perfect square :
x2+(29/30)x+(841/3600) =
(x+(29/60)) • (x+(29/60)) =
(x+(29/60))2
Things which are equal to the same thing are also equal to one another.
Solving 30x2+29x-1830 = 0 by the Quadratic Formula .
According to the Quadratic Formula, x , the solution for Ax2+Bx+C = 0 , where A, B and C are numbers, often called coefficients, is given by :
- B ± √ B2-4AC
x = ————————
2A
In our case, A = 30
B = 29
C = -1830
Accordingly, B2 - 4AC =
841 - (-219600) =
220441
Applying the quadratic formula :
-29 ± √ 220441
x = ————————
60
√ 220441 , rounded to 4 decimal digits, is 469.5114
So now we are looking at:
x = ( -29 ± 469.511 ) / 60
Two real solutions:
x =(-29+√220441)/60= 7.342
or:
x =(-29-√220441)/60=-8.309
Two solutions were found :
x =(-29-√220441)/60=-8.309
x =(-29+√220441)/60= 7.342