Answer: 17
Step-by-step explanation: ok so first to find the mean you add all the numbers then divide by how many numbers there is so basically 18 plus 15 plus 20 plus 15 then divide by 4 because there is 4 numbers and once you do that it is 17
Answer:
To prove that 3·4ⁿ + 51 is divisible by 3 and 9, we have;
3·4ⁿ is divisible by 3 and 51 is divisible by 3
Where we have;
= 3·4ⁿ + 51
= 3·4ⁿ⁺¹ + 51
-
= 3·4ⁿ⁺¹ + 51 - (3·4ⁿ + 51) = 3·4ⁿ⁺¹ - 3·4ⁿ
-
= 3( 4ⁿ⁺¹ - 4ⁿ) = 3×4ⁿ×(4 - 1) = 9×4ⁿ
∴
-
is divisible by 9
Given that we have for S₀ = 3×4⁰ + 51 = 63 = 9×7
∴ S₀ is divisible by 9
Since
-
is divisible by 9, we have;
-
=
-
is divisible by 9
Therefore
is divisible by 9 and
is divisible by 9 for all positive integers n
Step-by-step explanation:
Answer:
e^2 -7 = x
Step-by-step explanation:
2=ln(x+7)
Raise each side to the base of e
e^2 = e^ln (x+7)
The e^ln cancel
e^2 = x+7
Subtract 7 from each side
e^2 -7 = x +7-7
e^2 -7 = x