Plz and explain how i would write this when i answer it !

3x + 4y = 5 x- 3y = -7 solve by substitution

If you double the input of a function and it results in half the output, and if you triple the input and it results in a third of the output, what can be guessed about the function? check all that apply.

If a flying disk is 139 meters in the air and travels at an average of 13 m/s how long is it in the air