Distributive property means you multiply the number on the outside the parentheses (in this case it is 7) with every number/variable inside the parentheses ( in this case it would be 5 and -4) so...
7*(5 - 4) = (7 * 5) - (7 * 4)
Further evaluated you would get...
35 - 28
7
Hope this helped!
~Just a girl in love with Shawn Mendes