Analysis: According to the function image, the symbols of A and B can be determined from the quadrant where the linear function image is located, and both the straight line and the parabola pass through point A, so by substituting the coordinates of point A into the linear function or quadratic function, you can get b=2a, and the symbol of K can be determined according to the quadrant where the hyperbola is located.

Answer: Solution: ∵ According to the diagram, the coordinate of the intersection point A of a linear function and a quadratic function is (-2,0).

∴-2a+b=0，

∴b=2a.

∵ As can be seen from the figure, if the parabolic opening is upward, a > 0,

∴b>0.

The inverse proportional function image passes through the first and third quadrants,

∴k>0.

A, from the diagram, hyperbola is located in the first and third quadrants, then k > 0.

∴ 2a+k > 2a, that is, b < 2a+k 。

So this option is wrong;

b、∫b = 2a，

∴a=-k, then K.

∴k 0 is contradictory,

∴a=b+k is invalid.

So this option is wrong;

c、∫a > 0，b=2a，

∴b>a>0.

So this option is wrong;