Answer:
Eric's expression is :

and Andrea's is :

In Eric's expression, 20 represents the initial amount of substance with which he has started the experiment.
is the amount of substance left after each time period (in this case, each week).The variable w in this case represents the number of weeks.
Andrea's expression can be written as :

The one outside of parentheses represents the initial amount of the substance. The one inside of parentheses represents 100% of the original amount of the substance. 0.5 represents the 50% of the substance that is lost each time period. The variable w in this case represents the number of weeks.
Answer:

Step-by-step explanation:
The vertex form of a quadratic equation <em>y = ax² + bx + c:</em>
<em>y = a(x - h)² + k</em>
(h, k) - coordinates of a vertex
We have the equation <em>y = x² - 6x + 6</em>.
Convert to the vertex form:

Answer:
i think its num 4
Step-by-step explanation:
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Step-by-step explanation:
hold up let me work it out and i will answer with full explanation