What subjects other than math that use ratios

Which of the following of the following sets of side lengths could not form a triangle?

When the solutions to each of the two equations below are graphed in the xy-coordinate plane, the graphs of the solutions intersect at two places. write the y-cordninates of the points of intersection in the boxes below in order from smallest to largest. y=2x y=x^2-3

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.