Start with

Add 2x to both sides:

Subtract 21 from both sides:

Divide both sides by 5. Since it is positive, we don't have to change the inequality sign:

So, the answer is 
2x 3.50 = $7 notebook sale 1x 3.00 = $3 pen sale Total sale = $10.00 less $1.00 profit To find percentage of profit $1.00/$10.00 = .10 or 10%
Answer:
37 mph
Step-by-step explanation:
if he starts at 0 then goes to 20 then add another 35 which gives you 55mph then he slows down you decrease 11 which is 44 then decrease again 7 gives you 37mph
Y = kx
80 = 16k
k = 80/16 = 5
direct variation
The first 2 choices are corect