Answer:
The answer is

Step-by-step explanation:
The problem is

First we have to bring x to the other side se we subtract x from both sides

Then we have to put it in order so the answer is

2.b..........................
189
Because you have to turn it into a percentage in order to know how many per 1 percent. So multiply 420 by 100 and get 4.2 then you multiply it by 45 and you get 189 so 179 schools have a horse mascot