Zero because you combine 12z and 15z because they are like terms giving you 27z. The equation now looks like 27z-6=27z-5. Subtract 27z on both sides leaving you -6=-5 which is false. So the equation has 0 solutions.
FALSE it will not because there are two points with the same X value
False. An estimation gives you a rough amount of whatever it is that you're calculating.
Combine like terms and do the exponent first then for the decimals use a calculator
