[tex]\begin{gathered} a) \\ y-intercept\text{ is \lparen0,20\rparen} \\ \\ b) \\ P1(0,20) \\ P2(1,10) \\ slope=m=\frac{y2-y1}{x2-x1}=\frac{10-20}{1-0}=\frac{-10}{1}=-10 \\ The\text{ slope is -10} \\ \\ c) \\ y=mx+b \\ m=-10 \\ y=-10x+b \\ T\text{o find b using P1\lparen0,20\rparen} \\ x=0 \\ y=20 \\ 20=-10(0)+b \\ 20=0+b \\ b=20 \\ Hence,\text{ the linear equation is} \\ y=-10x+20 \end{gathered}[/tex]