Answer:
-2
Step-by-step explanation:
Lets factor
(x+2)(x+2)=0
x=-2
Answer:
Okapi 290 kg
Llama 160 kg
Step-by-step explanation:
Let weight of each llama be 
Let weight of each okapi be 
<em>Given, combined weight of 1 okapi and 1 llama is 450, we can write:</em>
<em>
</em>
<em>Also, average weight of 3 llama is 190 more than the average weight of 1 okapi, thus we can write:</em>
<em>
</em>
Now, substituting 2nd equation into 1st equation, we can solve for weight of 1 llama:

Each llama weights 160 kg, now using this and plugging into 2nd equation, we get weight of 1 okapi to be:

Each okapi weigh 290 kg
Answer:
A) True
Step-by-step explanation:
In an experiment that has the purpose of testing the efficacy of a procedure or drug, comparison is made against the efficacy of a placebo, a procedure or drug that is <em>intended to have no effect whatever</em>.
__
Famously, a placebo is often found to be nearly as effective (or even more effective) than the procedure or drug on trial. This effect is known as "the placebo effect."