XY Plane

[LSB]

I picked e because I was rushed. Whenn I tried to redo the question I multiplied out the brackets and plugged in 0 for X. This left me with a+b. Statement 1 defines a+b. So, Iwould say answer A should be the correct answer. What value does statement 2 add?

[LSB]

Anybody on this?

[ankur_arora]

IMO C..

As the equation represents a parabola that intersects x axis twice and y axis once.

the equation from question : y = x(x) + x(a+b)+ab
for it to intersect x axis we need a and b both

so the equation on substituting 0 for y becomes x(x) + (a+b)x +ab=0
this is a quadratic enq with roots -a and -b and can be written as:
x(x) - (-a-b) +ab=0
or
x(x) +x(Sum of roots)+ product of roots=0

1) provides -> sum of roots
2) provides -> product of roots

so answer is C

[ankur_arora]

modification to the earlier post::

the product is -ve so a and b differ in sign

a+b=-1 and ab=-6

=> a=-3 and b=2 or a=2 and b=-3
we get the two points