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:
x+1
Step-by-step explanation:
Answer:
v = 55
Step-by-step explanation:
Plug in the values provided into the equation
v = u + at
v = 23 + 8 * 4
Solve
v = 23 + 8 * 4
v = 23 + 32
<u>v = 55</u>
Answer:
She should have used One-half (9.4) (11.9) to represent the area of a single triangle
Step-by-step explanation:
The pyramid is composed by 4 triangles and 1 square
area of the square: base² = 9.4²
area of each triangle = 1/2*base*height = 1/2*9.4*11.9
surface area of the pyramid = 4*area of each triangle + area of the square = 4*(1/2*9.4*11.9) + 9.4²
