What is the first step when rewriting y=3x^2+9x-18

Which of the following expressions is equal to 2x^2+8

Cd is the perpendicular bisector of both xy and st, and cy=20. find xy.

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