I would like to know others' opinion for these ones

GmatTest

1. On XY plane. If a line goes through Point A (A, 5), A is not equal to 5,is the slope of the line<0? a. Line goes through (0, -2) b. Line goes through (5, A) I chose B,maybe it's wrong. I don't understand why people think it's D, what does the first condition tell you if you don't know what the value of A is? 2、一个多项式，X*X+B*X+16，求B？ 1） X*X+B*X+16=（X+C）^2,对于所有的X，及部分C成立 2） B>0 －－－－－－－－－－－－－－－ I don't quite get the choice others posted, C? For a specific value of c, there is always one specific value of b,if the equation does not hold for all c,doesn't it mean that there are some unknown value of c, in this case how do we know what's b. 3. An irregular pentagon ABCDE, AB=3,BC=2,CD=4,DE=5(I think it's 5, not 100% sure, or maybe it's 6), what are the possible values of AE? The choices are combinations of 5,10,15. I solved it with the charateristics of triangles, a+b>c, a-b

kitten369

for 3) you are wrong, you can't use the charateristics of triangle. I think 10 is possible too.you could form a pentagon with 10, but not 15, because 2+3+4+5(6)<15