How do you find the zeros, real and imaginary, of y= -9x^2-28x-73y=9x228x73 using the quadratic formula?

1 Answer
Apr 28, 2016

Zeros of y=-9x^2-28x-73y=9x228x73 are -14/9-sqrt(461)/9i1494619i and -14/9+sqrt(461)/9i149+4619i

Explanation:

To find zeros of y=-9x^2-28x-73y=9x228x73, one needs to find values of xx for which y=f(x)=0y=f(x)=0.

For ax^2+bx+c=0ax2+bx+c=0, solution is given by quadratic formula (-b+-sqrt(b^2-4ac))/(2a)b±b24ac2a. Hence for -9x^2-28x-73=09x228x73=0 or 9x^2+28x+73=09x2+28x+73=0,

x=(-28+-sqrt(28^2-4xx9xx73))/(2xx9)x=28±2824×9×732×9

= (-28+-sqrt(784-2628))/1828±784262818

= (-28+-sqrt(-1844))/1828±184418

= (-28+-sqrt(-4xx461))/1828±4×46118

= -14/9+-sqrt(461)/9i149±4619i