Answer:
Present Time
Let X= Eric's age (4/5)X= Seth's age
Question: What are their ages now?________________________________________________________________________
Past (21 years ago)
X-21 =Eric's age (4/5)X-21=Seth's age
2*[4/5(X-21]=Eric's age
Therefore, X-21= 2*[4/5(X)-21]=Eric's age Substitution
_______________________________________________________________________
X-21= 8/5 X - 42 Solve for "X" by adding 42 to both sides.
X-21+42=(8/5) X
X+21 = (8/5)X Subtract "X" from both sides.
21=(3/5)X Multiply both sides of equation by reciprocal of (3/5), which is 5/3
21*(5/3)= X Finish the problem to find value of "X," which is Eric's age.
Then find 4/5 (X)= Seth's age
D and B are the answers because they are the variables.
Answer:
x=38.5
Step-by-step explanation:

cos(x)=
x=38.5(correct to the nearest tenth)
The answer is 15.25 cubic inches