Is y=-4 a function or not a function

Which ordered pair (c,d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15

Examine the two-step equation. − 7 4 + x 4 = 2 which property of operations allows you to add the same constant term to both sides? amultiplication property of equality bdivision property of equality caddition property of equality dsubtraction property of equality

Need plz been trying to do it for a long time and still haven’t succeeded