Write using correct exponential notation:

1) 43 = x10
2) 0.00000269 = x10
3) 432,506 = x10
4) 0.00900 = x10
5) 93,000,000 = x10
6) 2,400,000,000 = x10
7) 0.0000000158 = x10
8) 56,000 = x10
9) 186,000 = x10
10) 432x10^-4 = x10
11) 0.00378x10^-3 = x10
12) 400x10² = x10