Question

If one root of the equation 3x² +ax +12 = 0 is 3 than a =?​

Answer 1

Answer:

Answer is

Step-by-step explanation:

ANSWER

3x2+ax−2=0

Since, one root is 1, then x=1

⇒  3(1)2+a(1)−2=0

⇒  3+a−2=0

⇒  a+1=0

⇒  a=−1

⇒  Now, it is given that ax2+6ax−b=0 has equal roots.

∴  b2−4ac=0

⇒  (6a)2−4(a)(−b)=0

⇒  36a2+4ab=0

⇒  36(−1)2+4(−1)b=0                 [ Substituting a=−1 ]

⇒  36−4b=0

⇒  4b=36

∴  b=9

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