Findthe value of k so that ithas two real and equal roots k+4x2+k+x+1
Answers
Correct question: Find the value of k so that it has two real and equal roots (k + 4x²) + (k + x) + 1
GIVEN :
(k + 4x²) + (k + x) + 1
We know that when there are two equal and real roots then,
Discriminant = 0
Discriminant formula = b² - 4ac
0 = (k + 1)² - 4(k + 4)(1)
0 = k² + 2(k)(1) + 1² - 4k - 16
0 = k² + 2k + 1 - 4k - 16
0 = k² - 2k - 15
Split the middle term
k² - 2k - 15 = 0
k² - 5k + 3k - 15 = 0
k(k - 5) + 3(k - 5) = 0
k + 3 = 0 or k - 5 = 0
k = -3 or k = 5
Therefore, the value of k is -3 or 5
QUESTIONS -
Find the value of k so that it has two real and equal roots (k + 4x²) + (k + x) + 1
Equations : (k + 4x²) + (k + x) + 1
Quadratic equation states that when the two equal root exist then their discriminant must be equal to zero
Formula of D = b² - 4ac
0 = (k + 1)² - 4(k + 4)(1)
0 = k² + 2(k)(1) + 1² - 4k - 16
0 = k² + 2k + 1 - 4k - 16
0 = k² - 2k - 15
By splitting middle term
k² - 2k - 15 = 0
k² - 5k + 3k - 15 = 0
k(k - 5) + 3(k - 5) = 0
k + 3 = 0 | k - 5 = 0
k = -3 or k = 5
Hence the value of k are - 3 & 5
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