Question

the roots of equation 9x^2-2(k+1)x+ 49=0 are equal , then k is?​

Answer 1

Answer:

k = -22 or 20

Step-by-step explanation:

Since roots of equation are equal,

b² - 4ac = 0

[-2(k+1)]² - 4 * 9 * 49 = 0

=> 4(k²+2k+1) - 1764 = 0

=> 4k² + 8k + 4 - 1764 = 0

=> 4k² + 8k - 1760 = 0

=> 4 (k²+ 2k - 440) = 0

=> k²+ 2k - 440 = 0

=> k² + 22k - 20k - 440 = 0

=> (k+22)(k-20) = 0

=> k = -22 or 20