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:
Therefore the required result is 9x-2y =0.
Step-by-step explanation:
Given equation are
x-3y =6.....(1)
-8x-y=6 .....(2)
Subtracting equation (2) from (1)
x - 3y = 6
-8x - y= 6
+ + - [ The sign of equation (2) will be change in case of
_________ subtraction and in case of plus the signs remains same ]
(x+8x)-3y+y=6-6 [ adding the like terms]
⇒9x-2y =0
Therefore the required result is 9x-2y =0.
It’s 3!! I checked on a calculator :)
Answer:
a) -6
b) 9
c) 27
Step-by-step explanation:
If I am understanding the question, and assuming the living room is a rectangle, then the border should be 80 ft
