Question

The value of a^3+ b^3 if 3^a=81 and 7^b=343 is:​

Answer 1

Answer:

91

Step-by-step explanation:

3^a = 81

3^a = 3⁴

taking 3 out , as it is the same base

so,

a = 4

7^b = 343

7^b = 7^3

so,

b = 3

ACQ,

a³ + b³ = 4³ + 3³

= 64 + 27

= 91

Answer 2

Answer:

Third proportional is 343

So, ⟹A:B::B:343

Doing product of the extremes and product of mean, we get

B

2

=343A⟶(1)

Also, A:B=1:7

So, B=7A

So, (7A)

2

=343A

A=7

B=7A=49

A+B=49+7=56