Lf=0.05m((1+12x10-6 °C-1)(25°C-15°C) me pueden ayudar con el procedimiento​

You can add the whole numbers as is.

2 + 16 = 18

Add the fractions with the same denominator.

Find the common denominator between 5 and 9.

The common denominator should be 45.

Write both fractions with a denominator of 45.

3/5 → 27/45

4/9 → 20/45

Add the new fractions as is:

27/45 + 20/45 = 47/45

Write 47/45 as a mixed fraction.

47/45 → 1 2/45

Add both the whole number and the mixed fraction.

18 + 1 2/45 = 19 2/45

Solution: C) 19 2/45g