What number has three digits after the decimal point and is equivalent to 2.5

Compare these two waves: the blue and orange waves have the same pitch, but the blue wave is louder. the blue and orange waves have the same volume, but the blue wave has a higher pitch. the orange wave has a higher pitch, but the blue wave is louder. the blue wave has a higher pitch, but the orange wave is louder.

How do i do this? i don’t understand

What is the solution set of the quadratic inequality x2- 5< 0? o {xl-55x55{x- 155x55){xl -55x5 15){x1 - 15 sx5/5)