So far it seems right. basically, your equation says:

The number (y) of bacteria is 1, and that multiplies by 10 times, as many times as there are days gone by (x) .

i.e. after one day, the bacteria has increased by a factor of 10....

So your second answer is correct.

Now, when is the number of bacteria equal to 100. Well, y is the number of bacteria, so

Depending on your grade, you either just KNOW that 10^2 is 100, or you use your log button. I won't go into that, in case you don't know about it.

The last part is the same...

Seems like you havent done logs yet, so .. whatever method your teacehr prefers