Determine the value of k so that the two roots of the equation x 2- kx -36-0 are equal-A- k -12B- k -12C- k-4D- k -6

The correct options are A k = 12 B k = 12We know that roots of the quadratic nbsp;equation is equal when nbsp;D = 0 ⇒b^2 4ac nbsp; = 0 So, from the equ ...

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Standard X

Mathematics

Discriminant

Determine the...

Question

Determine the value of k so that the two roots of the equation x² − kx + 36 = 0 are equal.

k = 12

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k = -12

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k = 4

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k = 6

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Solution

The correct options are
A k = 12
B k = -12
We know that roots of the quadratic equation is equal when D = 0
$\Rightarrow$ $b^{2} - 4 a c = 0$
So, from the equation x² − kx + 36 = 0
a = 1, b = -k and c = 36
$\Rightarrow$ $k^{2} - 4 (a c) = 0$
$k^{2} - 4 (36) = 0$
$k^{2} = 144$
$∴$ k = 12 or -12

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Determine the value of k so that the two roots of the equation x2 − kx + 36 = 0 are equal.

The correct options are A k = 12 B k = -12We know that roots of the quadratic equation is equal when D = 0 ⇒b2−4ac=0 So, from the equation x2 − kx + 36 = 0 a = 1, b = -k and c = 36 ⇒ k2−4(ac)=0 k2−4(36)=0 k2=144 ∴ k = 12 or -12

Determine the value of k so that the two roots of the equation x² − kx + 36 = 0 are equal.

The correct options are
A k = 12
B k = -12
We know that roots of the quadratic equation is equal when D = 0
$\Rightarrow$ $b^{2} - 4 a c = 0$
So, from the equation x² − kx + 36 = 0
a = 1, b = -k and c = 36
$\Rightarrow$ $k^{2} - 4 (a c) = 0$
$k^{2} - 4 (36) = 0$
$k^{2} = 144$
$∴$ k = 12 or -12