Answer:
Turn off battery supply → The electromagnet turns off.
Place a magnet care inside the coil of wire → The strength of the electromagnet increases.
Change the direction in which the current flows → The poles of the electromagnet reverses
900.9% would be 9.009 as a percentage.
It's 900% because it's a whole number and it's .9% because of the last 9 in the number (the thousandth - 3 digits after the decimal).
2(4z - 6 - 6) = 170 - 46
2(4z - 12) = 124 |use distributive property: a(b - c) = ab - ac
8z - 24 = 124 |add 24 to both sides
8z = 148 |divide both sides by 8
z = 18.5