Remember that scientific notation always contains a number between 0 and 10 that is multiplied by ten to some power. In this case, to get a number between 0 and 10 (7.2) we would move the decimal point once to the right. Since it is moving to ththe right, the exponent over the 10 will be negative, and it will be -1 because we moved the point once. So the answer is 7.2*10^-1
Hope this helps
