1. verify sin^4 x-sin^2 x= cos^4 x-cos^2 x is an identity.
2.verify sin(360o-theta)=-sin theta

1. isolate the variable, in this case, d. subtract 35.5 on both sides of the equation.2. 52 subtracted by 35.5 is 16.53. therefore your answer would be d= 16.5this is the basics of pre algebra, isolating variable through adding, subtracting, multiplying, and dividing, if you have any other questions to ask just comment!