Answer:
10. b
11. c
12. b
Explanation:
10. You have appropriately eliminated choices (a) and (d). To choose between (b) and (c), evaluate the function at x=1:
f(1) = 2·2¹ = 4
Only choice B has the graph going through the point (1, 4).
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11. Your subtraction is incorrect for -8 -(-2). The appropriate sum is -6, so the appropriate choice is C. (The coefficient of w in choice D should also give you a clue that something is wrong.)
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12. The greatest common factor is 9c³d², so choices C and D can be eliminated immediately. Choice A has the coefficient of 54 on the wrong term, so it, too, can be eliminated. The appropriate factorization is shown in choice B.