The sum of a certain number and a second number is -42. the first number minus the second number is 52. find the numbers

Let the first number be x and decide number be y
therefore x+y = -42
also. x-y = 52 using the process of elimination
we get: 2x = 10
we divide both sides by 2, which gives us x=5
then we substitute the value of x in the first equation
that gives us. 5+y = -42
thus. y = -47

Answer d; a supplementary angle = 180°, so if that angle = 150°, y would = 30°.