Sort out the cards as functions or non-function PLEASE HELP

Consider the diagram. which line segment has the same measure as st? rx tx sr xs

Solve the following simultaneous equation by using an algebraic method (either substitution or elimination) 2x + 3y=-4 4x-y=11

The perimeter of an equilateral triangle is 4 cm more than the perimeter of a square and the length of a side of the triangle is 8 cm more than the length of a side of the aware. find the length of a side of the equilateral triangle