A, B,C, D what’s the correct answer

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 (%)

Complete the solution of the equation. find the value of y when x equals to 28 x+3y=28

What are the domain and range of the function f(x)=2^x+1