How do you find the discriminant of $-21x ^ { 2} - 15x - 24$ ?

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Answer 1 · 2018-01-25T05:21:23

The discriminant is $-1791$ .

When an expression is given in standard form, $ax^2+bx+c$ , the discriminant is simply $b^2-4ac$ .

With this expression:

$\rightarrow b^2-4ac$

$\rightarrow (-15)^2-4(-21)(-24)$

$\rightarrow 225-2016$

$\rightarrow -1791$

Since the discriminant is negative, plugging the values of the above $a$ , $b$ , and $c$ into the quadratic equation will result in 0 real solutions.

There will be 2 imaginary solutions, though.

How do you find the discriminant of -21x ^ { 2} - 15x - 24-21x ^ { 2} - 15x - 24?