4x 10 to the 7th power times as much as 4 x 10 to the 3rd power

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

Asap! i'm not good math and i'm lost.

3x + 4y = 5 x- 3y = -7 solve by substitution