A is your answer! Because of how many sides it has.
We need to start from the innermost parenthesis and work our way out.
The first parenthesis is 
. These are not like terms because one involves a variable, while the other is a constant term. Two terms are summable if they involve the same power(s) of the same variable(s).
So, we can take one step outwards, and we arrive to the square brackets. We have
and 2z and -13z are like terms, so we can sum them:
Finally we arrive to the whole expression, which is
Because, again, 5z and 11z were like terms.
Answer: It is usefull.
Step-by-step explanation:
The regression squared talks to us about how well the model fits in the experimental data, where 0.0 means that the model does not fit at all, and 100% means that the model fits perfectly.
This is always true? well, really not, there are cases where you can have a regression square of 0.98, which would imply that the model is correct, but when you see the residual vs fit the plot, you may see some pattern, which implies that there is a problem with the model (you always expect to see randomness when you look at this graph). While for a prediction, this actually may work (at least in the range of the data points, outside this range the model and the data may not coincide at all)
Now, it still is useful in a certain range, so we can actually conclude that if R^2 = 0.949 represents a model that is useful for predicting the exam marks.
Answer:
66.5m^3 closest value
Step-by-step explanation:
7*7=47 m^3 area of square
12-7=5m length of triangle side
(7*5)/2=17.5 m^3 area of triangle
area of square + area of triangle = total area
47+17.5 =64.5 m^3
