Find the Domain and Range and Describe the Level Curves $x y$

question 371

Multiple Choice

Find the domain and range and describe the level curves for the function f(x,y) .
-f(x, y) = ln (5x + 4y)

• A) Domain: all points in the \(x y\)-plane; range: all real numbers; level curves: lines \(5 x + 4 y = c\)
• B) Domain: all points in the xy-plane satisfying \(5 x + 4 y \geq 0\); range: all real numbers; level curves: lines \(5 x + 4 y = c\)
• C) Domain: all points in the \(x y\)-plane satisfying \(5 x + 4 y > 0\); range: all real numbers; level curves: lines \(5 x + 4 y = c\)
• D) Domain: all points in the \(x y\)-plane satisfying \(5 x + 4 y > 0\); range: real numbers \(z \geq 0\); level curves: lines \(5 x + 4 y = c\)

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