If f (x) defined on R satisfies f (x + y) = f (x) + F (y) + 2XY (x, y ∈ R), f (1) = 2, then f (- 3) is equal to () A. 2B. 3C. 6D. 9

Let x = y = 0 {f (0) = 0, x = y = 1 {f (2) = 2F (1) + 2 = 6; let x = 2, y = 1 {f (3) = f (2) + F (1) + 4 = 12, then let x = 3, y = - 3 get 0 = f (3-3) = f (3) + F (- 3) - 18 {f (- 3) = 18-f (3) = 6, so choose C

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1. If f (x) defined on R satisfies f (x + y) = f (x) + F (y) + 2XY (x, y ∈ R), f (1) = 2, then f (- 3) is equal to () A. 2B. 3C. 6D. 9
2. If f (x) defined on R satisfies f (x + y) = f (x) + F (y) + 2XY (x, y ∈ R), f (1) = 2, then f (- 3) is equal to () A. 2B. 3C. 6D. 9
3. If the function f (x) defined on R satisfies f (x + y) = f (x) + F (y) + 2XY (x, y belongs to R), f (1) = 2, then f (- 2) is equal to
4. If f (x) defined on R satisfies f (x + y) = f (x) + F (y) + 2XY (x, y ∈ R), f (1) = 2, then f (- 3) is equal to () A. 2B. 3C. 6D. 9
5. Let f (x) = (2x + 3) / (x-1) (x is not equal to 1), the image of function y = g (x) and the image of function y = F-1 (x + 1) be symmetric with respect to the straight line y = x, then G (3) is obtained
6. Given the function f (x) = 2 ^ x + 2 ^ (AX + b), and f (1) = 5 / 2, f (2) = 17 / 4 (1) Find the value of a and B (2) judge the parity of F (x) (3) try to judge the monotonicity of F (x) on [negative infinity, 0] and prove it; (4) find the minimum value of F (x)
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