Which of the following expressions is not equal to the others?
A. cos 35º cos 37° - sin 35° sin 37°
B. cos 100° cos 28° + sin 100° sin 28°
C. cos 72°
D. COS 100° cos 28° - sin 100° sin 28°

the anser is B

Step-by-step explanation:cos  cos 35º cos 37° - sin 35° sin 37°°- COS 100° cos 28° - sin 100° sin 28°- cos 72°= cos 100° cos 28° + sin 100° sin 28°

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.