Answer:
Given the statement: One pound of grapes costs $1.55.
Let x be be the cost of 3.5 pounds of grapes.
Equivalent ratios states that the two ratios that express the same relationship between numbers.
Therefore, by equivalent ratio:

then, we have;

Cross multiply the above equation; we hve

x = 5.425
therefore, the cost of 3.5 pounds of grapes is, $5.425
Switch equation position, h=s-2*pi*r^2/2pir
First, you wrote -3x-7<20, that means -3x<20+7
or -3x<27 and we have x>-9
We draw the line of equation x= -9 and we have the set of solution is the haft of the plan on the right of the line x= -9