3x^2+9x+5=0 what is X?

Answer 1

quadratic formula
a=3
b=9
c=5

x = (-b+or - sqrt(b^2-4ac))/2a

x = (-(9)+ or - sqrt(9^2 - 4(3)(5))/2(3)
x = (-9 + or - sqrt(81-60))/6

answer
x = (-9 + sqrt(21))/6 and
x = (-9 - sqrt(21))/6

or it could be written
x = -3/2 + sqrt(21)/6 and
x = -3/2 - sqrt(21)/6

Answer 2

Subtract the 5 from both sides:
3x ^2 + 9x = -5
Divide by 3:
x ^2 + 3x = -5/3
Find the perfect square:
x ^2 + 3x + 9/4 = 9/4 - 5/3 = 7/12
(x + 3/2) ^2 = 7/12
Find the square root:
x + 3/2 = + or - (square root of 7/12)
x = + or - (square root of 7/12) - 3/2

Ok, yeah, you could use the quadratic equation, but where's the fun in that?
By the way, why'd I get a thumbs down? My solution is as correct as using the quadratic equation...and maybe actually teaches something too, instead of just plugging in numbers.
That's my two cents for ya.

Answer 3

d=b^2-4ac
d=81-60
d=21
A(root)=-b+-(d)^1/2/2a


A=-9+-(21)1/2/6

Answer 4

use the formula : -b+_ (sqrt(b^2-4ac )/2a this gives u the root sf the equation.. where the equation is..ax2+bx+c..try solving. i intensionally dint give u the solution > i want u to try it out... maths should be learnt.. u cant expect readymade solutions here..u wont enjoy the subject!

Answer 5

use the quadratic formula:

(-b (+/-) sqrt(b^2 - 4ac))/2a

in this case
a=3
b=9
c=5

therefore

x= (-9 (+/-) sqrt(21))/6

Answer 6

x = [- 9 ± √(81 - 60)] / 6
x = [ - 9 ± √21 ] / 6
x = [ - 9 ± 4.58 ] / 6
x = - 0.74, x = - 2.26