In the xy-plane, at what two points does the graph of y = (x+a)(y+b) intersect the x axis?
1. A + b =1
2. The graph intersects the y-axis at (0,-6)
1. A + b =1
2. The graph intersects the y-axis at (0,-6)
If x= 0, y=ab/(1-a)-----(1)
y=0, x= -a -------------(2)
A)a+b=1
if we replace b=1-a in (1) we get y=-a
Hence no particular solution for this equation.
B)Cuts y axis at (0,-6)
It implies ab/(1-a)=-6
ab= -6(1-a)-----(3)
There are two variables and one equation. Hence no solution
But if we combine both of these
replace b=1-a in (3) we get a = -6
which means (C)
