Answer:
y = -28 ÷ x
Step-by-step explanation:
The standard format of a inversely proportional equation goes by the format of y = k ÷ x. The question asks us to write an equation if y = 7 when x = -4 and y varies inversely with x.
So we substitute the values y = 7 and x = -4 in the equation y = k ÷ x
K = constant, we have to work this out
7 = k ÷ -4
7 × - 4 = k
k = - 4 × 7
k = -28
k = -28 So then we put this back into the original y = k ÷ x to find our final equation which is y = -28 ÷ x
Answer:
3 + 4p + 8t
Step-by-step explanation:
3+2[2p+4t]
Distribute
3 + 4p + 8t
There are no like terms to combine
Let's start from what we know.

Note that:

(sign of last term will be + when n is even and - when n is odd).
Sum is finite so we can split it into two sums, first

with only positive trems (squares of even numbers) and second

with negative (squares of odd numbers). So:

And now the proof.
1) n is even.
In this case, both

and

have

terms. For example if n=8 then:

Generally, there will be:

Now, calculate our sum:



So in this case we prove, that:

2) n is odd.
Here,

has more terms than

. For example if n=7 then:

So there is

terms in

,

terms in

and:

Now, we can calculate our sum:




We consider all possible n so we prove that:
Answer:
C = pi * d = 2 * pi *r
Step-by-step explanation:
The circumference of a circle is the distance around the circle. It can be found by multiplying the diameter times pi.
C = pi * d
We can replace the diameter with twice the radius
C = pi * 2 * r = 2 * pi *r
Answer:
-9
Step-by-step explanation:
2x + 7 = -11
2x = -11 - 7
2x = -18
x = -9