Question

9k square minus 8 K - 20 equals to zero by completing square method​

Answer 1

Solution:

9k²-8k-20=0

divide each term by 9, we get

=> k²-8k/9-20/9 = 0

=> k²-2*k*4/9 = 20/9

=> k²-2*k*4/9+(4/9)²=20/9-(4/9)²

=>(k-4/9)² = 20/9-16/81

=> (k-4/9)² = (180-16)/81

=> (k-4/9)²= 164/81

=> k -4/9 = ±√(164/81)

=> k = 4/9±2(√41)/9

Therefore,

k =(4±2√41)/9

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