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Advanced Math / Nonlinear functions Difficulty: Hard

The functions f and g are defined by the given equations.

fx=3+|-2x-x2|

gw=|-ww-1|-w+5

If f(-4)=c, where c is a constant, what is the value of gc?

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Explanation

The correct answer is - 4.9 . The value of f-4 is the value of fx when x=-4. Substituting - 4 for x in the equation fx=3+-2x-x2 yields f-4=3+-2-4--42, or f-4=3+-8, which is equivalent to f-4=3+8, or f-4=11. Since it's given that f-4=c, it follows that c = 11 and the value of gc is the value of g11. Substituting 11 for w in the equation gw=-ww-1-w+5 yields g11=-1111-1-11+5, or g11=-1.1-6, which is equivalent to g11=1.1-6, or g11=-4.9. Note that -4.9 and -49/10 are examples of ways to enter a correct answer.