The equation for the worth of car after x number of years is,
[tex]\begin{gathered} y=27000-3000\cdot x \\ =27000-3000x \end{gathered}[/tex]Substitute 3000 for y in the equation to obtain the value of x.
[tex]\begin{gathered} 3000=27000-3000x \\ 3000x=27000-3000 \\ x=\frac{24000}{3000} \\ =8 \end{gathered}[/tex]So after 8 years the worth of car is $3000.
