There really is no single "obvious" choice here...
Possibly the sequence is periodic, with seven copies of -1 followed by six copies of 0, or perhaps seven -1s and seven 0s. Or maybe seven -1s, followed by six 0s, then five 1s, and so on, but after a certain point it would seem we have to have negative copies of a number, which is meaningless.
Or maybe it's not periodic, and every seventh value in the sequence is incremented by 1? Who knows?
I'll go ahead and assume the latter case, that the sequence is not periodic, since that's technically somewhat easier to manage. We can assign the following rule to the

-th term in the sequence:


for

.
So the generating function for this sequence might be

As to what is meant by "closed form", I'm not sure. Would this answer be acceptable? Or do you need to find a possibly more tractable form for the coefficient not in terms of the floor function?
So,
Let x represent Joe's weight and y represent Jeff's weight.
"Joe weighs 20 lbs. less than twice Jeff's weight."
x = 2y - 20
"If Jeff would gain 10 lbs., then together they would weigh 250 lbs."
(y + 10) + x = 250
We now have our two open sentences.
x = 2y - 20
(y + 10) + x = 250
Get rid of parentheses.
x = 2y - 20
x + y + 10 = 250
We will use Elimination by Substitution.
2y - 20 + y + 10 = 250
Collect Like Terms.
3y - 10 = 250
Add 10 to both sides.
3y = 260
Divide both sides by 3.

Substitute again.

Multiply.

Subtract.

Check.
"Joe weighs 20 lbs. less than twice Jeff's weight."
Jeff's weight times two is 173 and one-third.
20 lbs. less than that is 153 and one-third lbs. Check.
"If Jeff would gain 10 lbs., then together they would weigh 250 lbs."
86 and two-thirds + 10 = 96 and two-thirds.
96 and two-thirds + 153 and one-third equals 250 lbs. Check.

Answer:
The number is -1/2
Step-by-step explanation:
Let x be the number
2x+8 = 7
Subtract 8 from each side
2x+8-8 = 7-8
2x = -1
Divide each side by 2
2x/2 =-1/2
x = -1/2
The number is -1/2
Since it is parallel, gradient must be the same so it will be 1/2
y=1/2x+c
-7=1/2(0)+c
c=-7
equation is y=1/2x-7
Step-by-step explanation:
SA=ph+2A, that is, perimeter × height+ twice area
p=21+20+29=70cm
h=22cm
70×22=1540cm
A=1/2 ×20×21=210×2=420
1540+420=1960cm2