- Perpendicular to y=9
- Slope is 0
Perpendicular lines have slope negative reciprocal to each other .
Equation of line in point slope form
[tex]\\ \rm\Rrightarrow y-y_1=m(x-x_1)[/tex]
[tex]\\ \rm\Rrightarrow y-11=\infty(x+8)[/tex]
[tex]\\ \rm\Rrightarrow \dfrac{y-11}{\infty}=x+8[/tex]
[tex]\\ \rm\Rrightarrow x+8=0[/tex]
[tex]\\ \rm\Rrightarrow x=-8[/tex]
Some formats of line
[tex]\boxed{\begin{array}{c|c}\boxed{\bf Form} &\boxed{\bf Equation} \\ \sf Slope\: intercept\:form &\sf y=mx+b \\ \sf Intercept\:form &\sf \dfrac{x}{a}+\dfrac{y}{b}=1\\ \sf Normal\:form &\sf xcos\omega+ysin\omega=p \\ \sf Two\: point\:form &\sf y-y_1=\left(\dfrac{y_2-y_1}{x_2-x_1}\right)(x-x_1)\\ \sf Point\:slope\:form &\sf y-y_1=m(x-x_1) \\ \sf Standard\:form &\sf Ax+By+C=0 \end{array}}[/tex]
