Simply distribute the -3 across the b and -7.
-3(b - 7) = (-3 * b) + (-3 * -7) = -3b + 21
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Answer:
Null hypothesis: 
Alternative hypothesis: 
The alternative hypothesis for this case is that at least one mean is different from the others.
And the best method for this case is an ANOVA test.
Step-by-step explanation:
For this case we wnat to test if all the mean length of all face-to-face meetings and the mean length of all Zoom meetings are the same. So then the system of hypothesis are:
Null hypothesis: 
Alternative hypothesis: 
The alternative hypothesis for this case is that at least one mean is different from the others.
And the best method for this case is an ANOVA test.
4.9÷7=0.7 because 49÷7=7, 4.9=49/10, and 7/10=0.7
Step-by-step explanation: If you take a look at the right side of the equation, a 3 is being added to our variable <em>x</em>.
If you were going to solve this equation, you must subtract 3 from the right side and the left side to isolate our variable.
You would end up with 4 = x.