Help Pls. This is Surface Area.!!

The length and a quarter of the width of a rectangle add up to 7 in, while the length and the width add up to 10 in. what are the rectangle's length and width?

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

Which represents the solution set of the inequality 5x-9 < 21? a. x < 12/5 b. x > 12/5 c. x > 6 d. x < 6