How can we check an orthographic drawing to be sure there are no missing lines

If you shift the linear parent function, f(x)=x, up 13 units, what is the equation of the new function?

Players on the school soccer team are selling candles to raise money for an upcoming trip. each player has 24 candles to sell. if a player sells 4 candles a profit of$30 is made. if he sells 12 candles a profit of $70 is made

The equation line of cd is y=-2x-2. write an equation of a line parallels to line cd in slope-intercept form that contains point (4,5)