Please help for 15 points, no absurd answers.

Wo audio speakers are placed on a vertical rail. speaker a is placed at head-level while speaker b is place at some variable height, \delta yδy, above speaker a. both speakers receive simultaneous input from a sine-wave generator so the speakers each produce a pure sinusoidal sound wave with a wavelength of 0.531 meters. calculate the lowest height that speaker b can be placed above speaker a to produce a minimum of sound heard by person standing \delta x = 7.86δx=7.86 meters directly in front of speaker a.

Both independent and dependent clauses

A4.0-cm tall light bulb is placed a distance of 32.0 cm from a concave mirror having a focal length of 16.0 cm. determine the image distance