700<=560+0.08x
x is total sales $
the 560 is the constant weekly pay, since we're only calculating for one week.
we're adding 0.08x to account for the 8% of the total sales
solve it for x:
700-560 <= 0.08x
140 <= 0.08x
1750 <= x
or x >= 1750
meaning she needs $1750 worth of sales that week to earn atleast $700
as for C) just draw a number line with the number 1750 in the middle and the right shaded because it is 1750 or more.