Question

Find value of 3a2+9 for a=10

Answer 1

Answer:

Since, 2a, a+10 & 3a+2 are in AP

Therefore,

⇒2a+3a+2=2(a+10)

⇒5a+2=2a+20

⇒3a=18⇒a=6

Hence, this is the answer.

Answer 2

Answer:

3

2

+

9

=

1

0

3a^{2}+9a=10

3a2+9a=10

3

2

+

9

−

1

0

=

0