If An angle measures 56 degrees. what is the measure of its supplement

Need ! give step by step solutions on how to solve number one \frac{9-2\sqrt{3} }{12+\sqrt{3} } number two x+4=\sqrt{13x-20} number three (domain and range) f(x)=2\sqrt[3]{x} +1

41/17 as a decimal rounded to the nearest hundredth

How is working backward similar to solving an equation?