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Work Shown:
[tex]f(\text{x}) = -2\text{x}^2+4\\\\f(4) = -2(4)^2+4\\\\f(4) = -2(16)+4\\\\f(4) = -32+4\\\\f(4) = -28\\\\[/tex]
Explanation:
Replace every x with 4. Then use the order of operations PEMDAS to simplify to a single number.