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.
The answer is AA Similarity
Answer:
It is 30 because it is the only one that makes sense if you do the math
Lets x = missing angle
x = 180 - (60+80)
x = 180 - 140
x = 40
answer
40
<span>15<span>(<span>6−g</span>)</span></span><span>=<span><span>(15)</span><span>(<span>6+<span>−g</span></span>)</span></span></span><span>=<span><span><span>(15)</span><span>(6)</span></span>+<span><span>(15)</span><span>(<span>−g</span>)</span></span></span></span><span>=<span>90−<span>15g</span></span></span><span>=<span><span>−<span>15g</span></span>+<span>90</span></span></span>