GEOM: ANSWER QUICKLY PLZ. BRAINLIEST.

Which values for a and b will create infinitely many solutions for this system of equations? ax-y=8 2x+y=b

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

Iknow its nothing to do with education, but what type of thing should i wrote here? ? : ) its for mcdonald's btw.