Hey there!
7 - 5x - (3 + 5x)
= 7 - 5x - 1(3 + 5x)
= 7 - 5x -1(3) - 1(5x)
= 7 - 5x - 3 - 5x
COMBINE the LIKE TERMS
= (-5x - 5x) + (7 - 3)
= -10x + 4
Therefore, your answer should be: -10x + 4
Good luck on your assignment and enjoy your day!
~Amphitrite1040:)