Answer:
Im gonna have to say 21 yd^2.
Step-by-step explanation:
L*W=A^2 so... 7*3=21
How can expressions be written and evaluated to solve for unknowns in the real world?
Writing expressions requires figuring out which quantity in a situation is unknown, and define a variable to represent that quantitiy.
We look for words in the problem that will help us out what kind of operation to use in a given situation.
Example:
Donna bought 5 chocolate bars, and then ate some. Write an expression to represent how many chocolate bars Donna has left.
If we let the variable c represent the number of chocolates Donna has eaten, then we can write the expression on how many bars Donna has left as: 5 - c
Answer: nickels = 13, dimes = 7, quarters = 14
<u>Step-by-step explanation:</u>
First, set up the equations for each coin:

Next, the sum of the coins is $4.85 so substitute and solve for the variable:
Nickels + Dimes + Quarters = Sum
(0.30 + 0.05d) + 0.10d + 0.50d = 4.85
0.30 + 0.65d = 4.85
0.65d = 4.55
d = 7
Lastly, plug the d-value into the quantity equation for the nickels and quarters to find their quantity.
nickels: 6 + d = 6 + (7) = 13
quarters: 2d = 2(7) = 14
(3a^4 * b^-2) * (2a^7 * b^-1)
= 6*a^(4+7)*b^(-2-1)
= 6*a^11*b^-3