if the discriminant of 5x²-2x-k=0 is 64 then find the value of k.
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Answered by
1
Answer:
3
Step-by-step explanation:
(b^2)-4ac=64
(-2^2)-4(5)(-k)=64
k=3
Answered by
9
EXPLANATION.
Discriminant = 5x² - 2x - k = 0. is 64
TO FIND VALUE OF K.
⇒ D = b² - 4ac = 0.
⇒ (-2)² - 4(5)(-k) = 64.
⇒ 4 + 20k = 64.
⇒ 20k = 64 - 4.
⇒ 20k = 60.
⇒ k = 3.
value of k = 3
MORE INFORMATION.
(1) = D > 0 Or b² - 4ac > 0 [ roots are real and unequal ].
(2) = D = 0 Or b² - 4ac = 0 [ roots are real and equal ].
(3) = D < 0 Or b² - 4ac < 0 [ roots are imaginary ].
(4) = a quadratic equation ax²+bx+c = 0 has two and only two roots.
their roots are = -b ± √b² - 4ac/2a.
(5) = if a > 0, then the quadratic expression ax²+bx+c ha no greatest value but it has least value,
⇒ 4ac - b²/4a at x = -b/2a.
(6) = if a < 0, then the quadratic expression ax²+bx+c has no least value but it has greatest value.
⇒ 4ac - b²/4a at x = -b/2a.
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