Question

Find the discriminant of
x2-4x+21=0​

Answer 1

$\mathbf\red{Given:-}$

• ${x}^{2} - 4x + 21$

$\mathbf\blue{To\:Find}$

• The discriminant

$\mathbf\green{Solution}$

${x}^{2} - 4x + 21$

Discriminant (D) = ${b}^{2} - 4ac$

In, ${x}^{2} - 4x + 21$

a = 1 , b = -4 and c = 21

(D) =

${b}^{2} - 4ac \\ \\ = {( - 4)}^{2} - 4 \times 1 \times 21 \\ \\ = 16 - 84 \\ \\ = - 68$

$\boxed{Discriminant ( D) = -68}$

__________________

Points to remember:-

Case I :-

If D < 0 ,

then the roots of the equation are unequal and not real. In this case, we say that the roots are imaginary.

Case II :-

If D > 0

Roots are real and unequal

Case III:-

If D = 0

The roots are real and equal

$\large\pink{\underline{{\boxed{\textbf{Be\:Brainly}}}}}$

Answer 2

Answer:

x²- 4x + 21 = 0

a = 1 , b= -4 , c = 21

∆ = b²- 4ac

∆ = (-4)² - 4(1)21

∆ = 16 - 84

∆ = - 68

Thank you