(Help!) I need somebody (Help!) Not just anybody (Help!) You know I need someone (Help!). Algebra question :)

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

Mr. vector door is buying two new cowboy hats all together the hats cost $75.12 the second heart cost twice as much as the first hat what is the price of the more expensive at round to the nearest hundredth

Aclothing designer is selecting models to walk the runway for her fashion show. the clothes she designed require each model’s height to be no more than y inches from 5 feet 10 inches, or 70 inches. which graph could be used to determine the possible variance levels that would result in an acceptable height, x?