(1,2times 10^-5)/(6times 10^-2)-0,9times 10^9

To solve this expression, we need to perform the division first and then subtract the second term.<br /><br />Given expression: $\frac {1,2\times 10^{-5}}{6\times 10^{-2}}-0,9\times 10^{9}$<br /><br />Step 1: Perform the division.<br />$\frac {1,2\times 10^{-5}}{6\times 10^{-2}} = \frac {1,2}{6} \times \frac{10^{-5}}{10^{-2}} = 0,2 \times 10^{3} = 2 \times 10^{2}$<br /><br />Step 2: Subtract the second term.<br />$2 \times 10^{2} - 0,9\times 10^{9} = 2 \times 10^{2} - 9 \times 10^{8}$<br /><br />Since the exponents are different, it's easier to convert them to the same exponent:<br />$2 \times 10^{2} = 2 \times 10^{2} = 2 \times 10^{2}$<br />$9 \times 10^{8} = 9 \times 10^{8} = 9 \10^{8}$<br /><br />Now, subtract the two terms:<br />$2 \times 10^{2} - 9 \times 10^{8} = -8,98 \times 10^{8}$<br /><br />Therefore, the correct answer is $-8,98 \times 10^{8}$.