PLEASE HELP with 2,3,& 4

due today

please number your answers

X+ y = 5 ; x - y =3 solve using linear combination

The graph shows the decibel measure for sounds depending on how many times as intense they are as the threshold of sound. noise in a quiet room is 500 times as intense as the threshold of sound. what is the decibel measurement for the quiet room? 20 decibels28 decibels200 decibels280 decibels

How can you find the magnitude of a vector, v = < x,y > , where the horizontal change is x and the vertical change is y?