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Answer:
-2cos²(x) +3cos(x) -1
Step-by-step explanation:
Use the "Pythagorean identity" to replace sin²(x).
sin²(x) +cos²(x) = 1
Then ...
2sin²(x) +3cos(x) -3 = 2(1 -cos²(x)) +3cos(x) -3
= -2cos²(x) +3cos(x) -1
-2cos(x)+3cos(x)-1
