Answer:
Her answer is wrong because she the object cannot hit the ground at negative seconds. She could’ve have used other methods because she used the quadratic formula. The advantages is that it works for every situation. The disadvantages is that it takes longer. She should’ve used a different method.
Step-by-step explanation:
Answer:
6 dm
Step-by-step explanation:
Triangle DBE is similar to triangle ABC, so their side lengths are proportional.
DE/AC = DB/AB
The length of DB can be found from ...
DB +AD = AB
DB = AB -AD = (15 -10) dm = 5 dm
So, we can fill in the proportion:
DE/(18 dm) = (5 dm)/(15 dm)
DE = (18 dm)·(1/3) . . . . . . . . . . simplify, multiply by 18 dm
DE = 6 dm
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It can be helpful to draw and label a figure.
We can model this situation as a system of linear equation, where n is the number of nickels and q is the number of quarters.

Solving the system of equations, there are 67 nickels and 19 quarters.