S=400+0.15c
0.15 is the slope which represents that she gets $0.15 per sale she makes.
Sin2x+cos2x=1
2sinxcosx+2cos^2x-1=1
2cosx(cosx+sinx-1)=0
2cosx=0 cosx+sinx=1
True
I did this with double angle formulas. sin2x=2sinxcosx, and cos2x=2cos^x-1. With plugging this in, I used factoring. At the end, there are two factors. One of the factors is cosx+sinx-1=0, which is cosx+sinx=1. Therefore, the answer is true.
There are 7 students in the cafeteria that is not eating salad or sandwiches
10>X>0 this is x being greater than 0 and less than 10