Blank divided by 7 is greater than 800

How many different three-digit numbers can be formed using the digits 1 comma 2 comma 9 comma 6 comma 4 comma 3 comma and 8 without repetition? for example, 664 is not allowed.

True or false: the graph of y=f(bx) is a horizontal compression of the graph y=f(x) if b< 1

Find the magnitude, correct to two decimal places, made by each of the following with positive direction of the x axis a) y= x the answer is 45° but i don’t know how