MAT223 Lecture 03

• Activity 1:
  • Draw the line with $y=x+1$
  • How many points $(x,y)$ satisfy the equation?
  • Anything on the line.

        left=-5; right=5;
        top=5; bottom=-5;
        ---
        y=x+1
        y=2x-1
        y=-x
    

• $\left[\begin{array}{ccccc}1& 0& 1& 1& 2\\ 0& 1& 2& -1& 1\end{array}\right]$
• $x_1+x_3+x_4=2$
• $x_1=2-x_3-x_4$
• $x_2+2x_3-x_4=1$
• $x_2=1-2x_3+x_4$
• $x_1=2-s-t$
• $x_2=1-2s+t$
• $x_3=s$
• $x_4=t$