How long does the string have to be in order to produce a first harmonic
of 220 Hz on a guitar? The speed of
the wave is 435 m/sec.

Make them both to where they have the denominator of 18that makes 3/2 equal 27/18 and 1/9 equal 2/18so now you have  27/18x+5=2/18subtract 5 from the other sideso now you have 27/18x+2/18-5then subtract 2/18 from 27/18 to get 25/18x=-5then divide 25/18 by -5 and your answer will be  -5/18

The geological theory that states that pieces of earth's lithosphere are in constant slow motion is the theory of plate tectonics.

It is increased due to the doppler effect. (apex)