What does it mean for an equation to express y in terms of x?

The larger of two number is 4 less than twice the smaller number. the sum is 41. find the numbers

Yahir designs bracelets. he uses between 9 and 15 red and yellow beads in the ratio of 2 red bead to 5 yellow beads. drag the beads into the container to meet these requirements

Determine if the equation defines y as a function of x: 2xy = 1. yes o no