intersections

[bob4000]

how wud i do the following:

1.ax+by=c, y=2ax
2.y=mx+c, y=-mx+d
3.ax-by=1, y=x
4.some values for a,b and c for which equation does not represent a straight line, give egs

ive dun simpler versions of 1-3 but i haven't come across the above, so cud someone please tell me a simple method of working them out. thnx

[faust9]

I'm having trouble understanding what you want. Are you trying to solve all six equations simultnaeously? 5 unknowns for 6 equations means you have a dependent equation in that lot. What class is this for? Linear Algebra requires a slightly diffferent approach than regular algebra. Do you know how to use matrices?

Anyway, a little more information presented slightly more clearly would help here.

[bob4000]

all the questions are separate, hence the numbering of each question. its as level and ive jut started this work so i need a bit of help