Solve the problem.An airplane flies 450 miles with the wind and 330 against the wind in the same length of time. If the speed of the wind is 20, what is the speed of the airplane in still air?
A. 55 mph
B. 120 mph
C. 135 mph
D. 130 mph
Answer: D
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Solve.From a boat on the lake, the angle of elevation to the top of a cliff is 30°54'. If the base of the cliff is 1753 feet from the boat, how high is the cliff (to the nearest foot)? 
A. 1049 ft B. 1062 ft C. 1052 ft D. 1059 ft
Evaluate the indicated function with the given information.Find the value of sin 
if tan ? = -0.6745 (90° < ? < 180°).
A. 0.4695 B. 0.9563 C. 0.2924 D. 0.8829
Solve by graphing. x + 0.5y = 12x + y = 4
A. 
B. No solution
C. 
D. 
Secret messages can be encoded by using a code and an encoding matrix. If we have the code:
and an encoding matrix E, we can encode a message by taking every two letters of the message, converting them to their corresponding numbers, creating a 2 × 1 matrix, and then multiplying each two numbers by E. The message may be unscrambled with a decoding matrix which is the inverse of the coding matrix, E-1. Determine if the given pair of encoding matrices are inverses of each
other.
and 
What will be an ideal response?