Answer:
= 
To find equivalent fractions, multiply be any number that is the same for the numerator/denominator
You can also divide, but it must be divisible by both the numerator/denominator
Constraints are simply the subjects of an objective function.
The inequality that represents the constraint is: 
Represent the number of hats with x, and the number of scarves with y.
From the question, we have:
- He spends 12 hours to knit a hat
- He spends 6 hours to knit a scarf
So, the equation of the total time spent is:

This time spent is not more than 20 hours.
So, the inequality is

Hence, the inequality that represents the constraint is: 
Read more about constraints at:
brainly.com/question/24574823
Answer:
The answer is when they work 4 hours x=4
Step-by-step explanation:
510 + 80x = 650 + 45x
80x - 45x = 650 - 510
35x = 140
x = 140/35
x = 4 hours
15 quarters= $3.75
21 nickels =$1.05
______________
36 coins = $4.80