Question

If an = 3n-2, then value of a7 + a8 is​

Answer 1

Given,

$\boxed{\sf{a_n = 3n-2}}$

Here we have to just substitute the value of n.

• Finding a₇,

$\sf{\implies a_7 = (3\times 7)-2}$

$\sf{\implies a_7 = 21-2}$

$\sf{\implies a_7 = 19}$

• Finding a₈,

$\sf{\implies a_8 = (3\times 8)-2}$

$\sf{\implies a_8 = 24-2}$

$\sf{\implies a_8 = 22}$

• Finding a₇+a₈,

$\sf{\implies a_7+a_8 = 19+22 }$

$\sf{\implies a_7+a_8 = 41 }$

Therefore,

$\boxed{\sf{\therefore a_7+a_8 = 41 }}$

Answer 2

Answer:

Here we have to just substitute the value of n.

Finding a₇,

\sf{\implies a_7 = (3\times 7)-2}⟹a

7

=(3×7)−2

\sf{\implies a_7 = 21-2}⟹a

7

=21−2

\sf{\implies a_7 = 19}⟹a

7

=19

Finding a₈,

\sf{\implies a_8 = (3\times 8)-2}⟹a

8

=(3×8)−2

\sf{\implies a_8 = 24-2}⟹a

8

=24−2

\sf{\implies a_8 = 22}⟹a

8

=22

Finding a₇+a₈,

\sf{\implies a_7+a_8 = 19+22 }⟹a

7

+a

8

=19+22

\sf{\implies a_7+a_8 = 41 }⟹a

7

+a

8

=41

Therefore,

\boxed{\sf{\therefore a_7+a_8 = 41 }}

∴a

7

+a

8

=41

hope this helps