Short answer: (-8)^2 + 8 x -8 =
0
Use PEMDAS
"Evaluate the expression" just means solve until you can't simplify anymore. You must solve it in a certain order according to
PEMDAS: Parentheses, Exponents, Multiply, Divide, Add, Subtract.
What does the beginning of the expression look like? It is

.
According to PEMDAS, you must solve what is in the parentheses *first*. But, since there is only a number (-8), there is nothing to solve for and you can move on to exponents.
The squared symbol, the little 2, means you have to square what is *inside* the parentheses.

= 64, because -8 times itself is 64.
Next comes multiplication. Remember, we are not working from left to right. We must multiply the values on the far right before we do any adding, because multiplication comes *before* addition.
(64) + (8 times -8)
(64) + (-64)
Finally, we can add. In this case, because we are adding a negative number, we are really subtracting. 64 + -64 equals 0.
Answer:
a)
b) 
c) They'd have lost $1000 if they had sold no calendars.
Step-by-step explanation:
a) The equation of the line in Slope-Intercept form is:

Where "m" is the slope and "b" is the y-intercept.
In this case we know that "y" represents the profit of loss and "x" the number of calendars sold.
Then, according to the exercise, the line passes through these two points:
and 
Then, we can find the slope of the line with the formula 

Now, we can substitute the slope and one of those points into
and solve for "b":

Then, subtituting values, we get that the equation that describes the relation between the profit of loss and the number of calendars sold, is:
b) The slope of the line is the profit they made from selling each calendar

c) The y-intercept is the amount they would have lost if they had sold no calendars:

They'd have lost $1000 if they had sold no calendars.
You are X, if your friend is 1.2 times taller than you= 1.2X
That's why 64.5=1.2X
X=53.75
But you should write 53.8 inches tall. Because there is one number after point.
<span>As a result, you are 53.8 inches tall
</span>