Question

HOW DO I FIND THE DISCRIMINANT OF 2X^2+11X-21=0 ?

Answer 1

See formula attached.

Answer 2

11^2 -4*2*(-21)= ? @stupidfresh305

Answer 3

and when the discriminant, \(b^2 -4ac \gt 0\) , you have 2 solutions, \(b^2-4ac < 0\), you have 0 solutions, while \(b^2 -4ac = 0\) would render 1 solution :)

Answer 4

Do you still need help with this question? Because you just have to do what @Jhannybean suggested.

Answer 5

The question is to give the discriminant. The nature of the roots as determined by the discriminat is not part of the question as I read it.

Answer 6

Simplifying
2x2 + -11x + -21 = 0

Reorder the terms:
-21 + -11x + 2x2 = 0

Solving
-21 + -11x + 2x2 = 0

Solving for variable 'x'.

Factor a trinomial.
(-3 + -2x)(7 + -1x) = 0

Subproblem 1
Set the factor '(-3 + -2x)' equal to zero and attempt to solve:

Simplifying
-3 + -2x = 0

Solving
-3 + -2x = 0

Move all terms containing x to the left, all other terms to the right.

Add '3' to each side of the equation.
-3 + 3 + -2x = 0 + 3

Combine like terms: -3 + 3 = 0
0 + -2x = 0 + 3
-2x = 0 + 3

Combine like terms: 0 + 3 = 3
-2x = 3

Divide each side by '-2'.
x = -1.5

Simplifying
x = -1.5
Subproblem 2
Set the factor '(7 + -1x)' equal to zero and attempt to solve:

Simplifying
7 + -1x = 0

Solving
7 + -1x = 0

Move all terms containing x to the left, all other terms to the right.

Add '-7' to each side of the equation.
7 + -7 + -1x = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -1x = 0 + -7
-1x = 0 + -7

Combine like terms: 0 + -7 = -7
-1x = -7

Divide each side by '-1'.
x = 7

Simplifying
x = 7