How to order decimals from least to greatest with different decimals places?

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

Which number produces a rationale number when multiplied by 1/5

Answer this two poles, ab and ed, are fixed to the ground with the of ropes ac and ec, as shown: two right triangles abc and edc have a common vertex c. angle abc and edc are right angles. ab is labeled 13 feet, ac is labeled 15 feet, ec is labeled 10 feet, and ed is labeled 4 feet.what is the approximate distance, in feet, between the two poles? 11.14 feet16.65 feet14.35 feet15.59 feet