# MilyYang

Most popular questions and responses by MilyYang-
## Maths

If the straight line x-y=k and the circle x^2+y^2+2x-4y-1=0 intersect at A and B, then the x-coordinate of the mid-point of AB is _ ? A. 1+k B. 1-k C. (1+k)/2 D. (1-k)/2

*asked on May 8, 2014* -
## Maths

Let f(x)=3x^2-6x+k, where k is a constant. If the y-coordinate of the vertex of the graph of y=f(x) is 7, then k=?

*asked on May 8, 2014* -
## Maths

If the variance of the four numbers a,b,c and d is 9, then the variance of the four numbers 14-a, 14-b, 14-c and 14-d is _? A. 5 B. 9 C. 23 D. 121

*asked on May 8, 2014*