book Maths Puzzle Numerical Ability

this is for quadratic formula and parabolas which could be the graph of the parabola a.y=x2=1,b.y=x2-1,c.y=-x2=1,d=-x2-1

Read Solution (Total 0)

book Other Question

Describe a first step for solving each system using elimination. Then solve each system.

2x-y=6
-3x+4y=1
I'm not understanding the elimination technique that my teacher is explaining. My problem is:
3x+3y-2z=-32
x-3y+z=11
-x-3y+3z=23

I don't understand how to substitute after