Which of the following scale drawings is an enlargement of the original object?

Third picture is the enlarged image of the original object.

Step-by-step explanation:

In the attached file original image is of a triangle having sides with the measurement of 21cm , 21cm, and 30 cm Or .21m , .21m , .30m

Now first image is a triangle having sides 0.21m, 0.21m and 0.30m

So the measurements are the same as original with no enlargement.

In second picture given triangle is having sides 210mm, 210mm, and 300mm.

Which is again same as original picture with no enlargement.

In third picture given sides of the triangle are 0.42m, 0.42m and .30m

which are double of the original picture with a scale enlargement = Sides of the third picture/ sides of original picture = .42m/.21m =.41m/.21m=.30m/.15m= 2

Therefore third triangle is the double of the original one.

In fourth picture sides of the given triangle are 70mm. 70mm, 50mm Or 7cm, 7cm, 5cm

Now the ratio of third and original picture = 7/21=7/21 ≠5/30 which are equal

Therefore third triangle is not an enlarged image of the original triangle.

Third picture is the enlarged picture of original one.

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9