An expanding rectangle has a fixed width of 7 inches and an initial length of 0 inches. the length of the rectangle begins increasing at 2.7 inches per second. write a formula that expresses the perimeter of the rectangle, p (in inches), in terms of the length of the rectangle, l (in inches).

P = (5.4 inches/sec) t + 14 inches for t > 0

Step-by-step explanation:

A formula for the length of this rectangle is L = (2.7 inches/sec) t, where t is the number of seconds.

The standard formula for the perimeter of a rectangle is P = 2L + 2W.

Substituting  (2.7 inches/sec) t for L, we get:

P = 2( (2.7 inches/sec) t ) + 2(7 inches) for t > 0.

This may be simplified slightly:  

P = (5.4 inches/sec) t + 14 inches for t > 0

1 11/21

Step-by-step explanation:

Data: 2/3+6/7=x

Step one, Find the common denominator

(2/3)x7(for each number)=14/21

(6/7)x3(for each number)=18/21

Reason: To add fractions, you always have to find the common denominator(so you can make the denominator the same for each fraction). The common denominator of 3 and 7 is 21 and since what you do to the bottom has to be done to the top, you multiply 2 by 7 and 6 by 3 to end up with 14/21 and 18/21.

Step two, add

14/21+18/21=32/21=1 11/21

Reason: Since we have our common denominators, we just have to add and, with fractions, you only add the top(numerator) and not the bottom(denominator) you end up with 32/14 but when made into a mixed fraction(by dividing the bottom into the top and leaving the remainder on the top) you get 1 11/21 which can't be simplified.

So since it can't be simplified, it's your answer

I hope this helps!