Hello everyone. Attached is a screenshot of one of the questions given to us in our calculus homework and I attempted to solve it but seemed to have failed at it... The question says "perpendicular," so I went through some of my old notes and found that the rule is to get the negative inverse of the slope. The negative inverse of the given equation is supposed to be 1, but when I tried solving, the slope I arrived at is -2. Sorry if I'm not making any sense here...

Please point me in the right direction. Thank you so much!