Please help, determine the domain

What is x and y (use substitution? ) 5x+3y=38 and y=3x+8?

Acylinder has volume 45π and radius 3. what is it’s height?

Determine the common ratio and find the next three terms of the geometric sequence. 10, 2, 0.4, a. 0.2; -0.4, -2, -10 c. 0.02; 0.08, 0.016, 0.0032 b. 0.02; -0.4, -2, -10 d. 0.2; 0.08, 0.016, 0.0032 select the best answer from the choices provided a b c d