Given,
The expression is,
[tex]f(x)=y=-0.06x^2+1.2x[/tex]For x-intercept taking y = 0,
Substituting the value of y then,
[tex]\begin{gathered} 0=-0.06x^2+1.2x \\ -1.2x=-0.06x^2 \\ \frac{1.2}{0.06}=x \\ x=\frac{1.2}{0.06} \\ x=20 \end{gathered}[/tex]