-2, -5, -8
You're subtracting three each time.
Number of apples=12 times numer of bags=12n
neeeds at least 75 apples (1 per student)
12n≥75
divide both sides by 12
n≥6.25
can't buy 0.25 of a bag
7
needs to buy 7 bags
Let
x---------> the thickness of the frame in feet
At-------> Area of the mirror and the frame in square feet
we know that
------> equation 
--------> equation 
equate equation
and equation 

therefore
the answer is the option

The answer to 8+11 is 19 because 8+1 is 9 so 11+8 is 19