7. A signal can be formed by running different colored flags up a pole, one above the other. Find the number of different signals
consisting of 7 flags that can be made if 3 of the flags are white, 3
are red, and 1 is blue.
A) 15
B) 9
C) 140
D) 35

Look, when you want to do something like put it like x^2. x2 could mean x² or x₂. so to clear confusion, know the notation. to find the product multiply the x's and you get -8x and the y's and you get 6y. since it's all being multiplied it is just -8x6y, or answer a. although the better answer is -48xy(combining -8 and 6) because you should multiply constants whenever you can.