How do you solve the quadratic using the quadratic formula given 3x211x=814x over the set of complex numbers?

1 Answer
Aug 30, 2016

Solution is 121056 and 12+1056

Explanation:

For the equation ax2+bx+c=0, the roots are given by x=b±b24ac2a. As can be seen type of roots depend upon discriminant b24ac. If it is negative, roots are complex and if it is a complete square (and coefficients are rational), roots are rational.

In the equation 3x211x=814x or 3x2+3x8=0, the discriminant is (3)24×3×(8)=9+96=105, which is not a complete square and hence roots are irrational (not complex as mentioned in question).

Roots are x=3±1052×3

= 3±1056

= 12±1056

Hence solution is 121056 and 12+1056.