There are many ways to do this depending on the property you have to use:
If you use the distributive property, you need to distribute 3/4 to -10 and 2/5. Distribute means you will multiply it so your resulting equation will be this:
Before you can add, you need to first make them like terms because you cannot add unlike fractions. Get the LCD and form your new equation:
Now you can just add them together to get:
and then simplify your fraction:
or - 
The whole fraction becomes negative because when you divide integers and of them is negative, the final answer will be negative.
If you use the distributive property, you need to distribute 3/4 to -10 and 2/5. Distribute means you will multiply it so your resulting equation will be this:
Before you can add, you need to first make them like terms because you cannot add unlike fractions. Get the LCD and form your new equation:
Now you can just add them together to get:
and then simplify your fraction:
The whole fraction becomes negative because when you divide integers and of them is negative, the final answer will be negative.