A rectangle has an area of 21x+81. If the width is 3 units, what is the length of the rectangle

(7x + 27) units

Step-by-step explanation:

A rectangle is a quadrilateral (has four sides) in which opposite sides are equal and parallel, also all the angles are equal. The area of a rectangle is given as:

Area = Length × Width

Given that the area of the rectangle is 21x + 81 and the width is 3 unit, to find the length of the rectangle, we have to use the formula of the area and then get the length. Therefore:

Area = Length × Width

21x + 81 = Length × 3

Length  = (21x + 81) /3

Length  = 7x + 27

The length of the rectangle is 7x + 27 units

3x^3-x^2+6x-9

d

step-by-step explanation:

hello and welcome!

so, when we see the words "proportional" along with a table, we need to know that we're looking numbers that divide by the same thing.

looking at this table, we simply have to do a trial and error, and divide to see which numbers have the same quotient. if you look at choice a & c, they both have equal quotients for three of the numbers, with one exception, so those can't be the answer. looking at b, there is no similarity, so that can't be it. then, we see d; if you divide all the numbers in the table, you'll see that they all divide by two, which is a proportional relationship, and our answer!

also, always remember that the x will always be the number that goes into y, and somewhere behind this table, is a formula. for this specific table, the formula would be:

since our x-value is being divided by two to get the y-value. and if they were to ask for more numbers in the series, this is the formula you would use to find them.