I have written the expression for a char variable x.The isupper(x) will return true if the character x is upper case and false if the character x is lower case.
I have stored the returned value to a bool variable b .So the value of variable b will be true only when the x is in uppercase and false when b is lower case.
Significant figures are numbers after the decimal point, which have usually been rounded. There are four numbers after the decimal point, so there are 4 significant figures.
She is starting at 4000, so that is the y-intercept of the graph. She is descending at 40 feet per minute, so her rate of change or slope is -40. The graph would look like this: