Mary enlarged a 4-by 6-inch photo a 10 by 15-inch photo.what is the scale factor of the dilation

The scale factor of the dilation is given  by:
(new length of the photo)/(old length of the photo)
the dimensions of the old photo is 4 in by 6 in
the dimensions of the new photo is 10 in by 15 in
length of old photo=6
length of new photo=15
scale factor=15/6=2.5 

Hello from MrBillDoesMath!

#11. Your choice, 3x + 1 <= 4, is correct

#13 Your choice, 8p +5 > 21. is correct

Discussion:

#11,    Let's explore:  3x + 1 <= 4

3x + 1 <= 4 =>

3x + 1 -1 <= 4 - 1  =>                         (subtract 1 from both sides)

3x <= 3 =>

x <=1

which matches the red line segment shown.  In the diagram, the point x = 1 is included (a solid dot) as in our solution x <=1.

#13. The second radio button,  the one you selected, is correct. Let's explore:

8p + 5 > 21 =>

8p + 5 -5 > 21 - 5                    (subtract 5 from both sides)

8p > 16                                    (as 21-5 = 16)

p > 2                                        (divide both sides by 8)

Note that this solution, like the graph ("open circle" at 2) does NOT include the point p = 2

Regards,  

MrB

P.S.  I'll be on vacation from Friday, Dec 22 to Jan 2, 2019. Have a Great New Year!