144 : [7. 3²-4². (10.3 -3³)]

First, let's simplify the expression inside the square brackets:

10.3 - 3³ = 10.3 - 27 = -16.7

Now, let's simplify the expression inside the parentheses:

3² - 4² = 9 - 16 = -7

Now, let's substitute the simplified values back into the original expression:

144 : [7. -7. (-16.7)]

Next, let's simplify the expression inside the square brackets:

-7. (-16.7) = 7 * 16.7 = 116.9

Now, let's substitute the simplified value back into the original expression:

144 : [7. 116.9]

Finally, let's simplify the expression inside the square brackets:

7. 116.9 = 7 * 116.9 = 818.3

Therefore, the final answer is:

144 : 818.3