Write the equation for the vertical line that passes through the point (-7,5)

问题描述:

Write the equation for the vertical line that passes through the point (-7,5)
我感觉这题没讲完~

翻译:写出过点(-7,5)的垂直线的方程.
但是为什么只有一个点呢?过一个点怎么有垂线呀?