(x+3)+49=90 how would I solve for x

You are making a battery for a science project. you have copper wire for your first electrode. you need to choose a conductor, a second electrode, and a device to plug into your battery. you have already chosen a lemon conductor. complete each statement below about the options that include a lemon conductor.

Idon’t understand! use slope intercept form to solve: through: (2,5) slope= undefined

With number 11 ( show how you got the answer)