40 points and brainlest answer if there is not enough information just say 'not enough info'

Ill mark the brainliest if you me with the these three questions 7,8,9

Find an equation of the line perpendicular to the graph of 28x-7y=9 that passes through the point at (4,1)

Acompany that manufactures and sells guitars made changes in their product range. from the start they had 20 models. then they reduced the number of models to 15. as a result, the company enjoyed a 10% increase in turnover. - how much did the stock level change? in (%)