The area of a rectangle is represented by 12n^2 - 19n – 21. If the width is 3n - 7, which expression represents the perimeter? A. 7n - 4
B. 7n + 4
C. 14n - 8
D. 14n + 8
pls help!!!

C 14n - 8

Step-by-step explanation:

area of rectangle = length × width = 12n² - 19n - 21

width = 3n - 7

so, what do we need to multiply with width to get the expression of the area ?

4n + 3

(because we think, what do we need to multiply 3n with to get 12n², and what to multiply -7 to get -21)

control : (3n-7)×(4n+3) = 12n²-28n+9n-21 = 12n²-19n-21

perimeter is now 2× length + 2× width

p = 2(3n-7) + 2(4n+3) = 6n - 14 + 8n + 6 = 14n - 8

answer: 59

step-by-step explanation:

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have