Answer:
see explanation
Step-by-step explanation:
the sum to n terms of an arithmetic sequence is
= 
[2a + (n - 1)d ]
where d is the common difference and a is the first term
here d = 9 - 7 = 7 - 5 = 2 and a = 5, hence
= [(2 × 5) + 2(n - 1) ]
= (10 + 2n - 2)
= (2n + 8)
= n² + 4n
When sum = 165, then
n² + 4n = 165 ← rearrange into standard form
n² + 4n - 165 = 0 ← in standard form
(n + 15)(n - 11) = 0 ← in factored form
equate each factor to zero and solve for n
n + 15 = 0 ⇒ n = - 15
n - 11 = 0 ⇒ n = 11
but n > 0 ⇒ n = 11
Answer:
4,1
Step-by-step explanation:
(x-4)(x-1)
x=4 or x=1
There are two expressions which do not match with the written descriptions to ist right.
Those are:
1) (4x - 3)^2 - 1: see that the written description does not square the difference of 4x and 3
2) 3(5x^2 + 14x + 7): see that the written description tells that 5 is added to the square ox x, which is not what the expression shows.
The other 4 expressions match with the written descriptions.
So, you can choose those other 4 expressions.
Answer:
The exact value of its surface area = 144π m²
The exact value of its volume = 288π m³
Step-by-step explanation:
∵ The diameter of the sphere is 12m
∴ The radius of the sphere = 12 ÷ 2 = 6m
∵ The surface area of the sphere = 4πr²
∴ The surface area = 4 × π × 6² = 144π m²
∵ The volume of the sphere = 4/3 πr³
∴ The volume = 
= 288π m³
