First you have all ten books, but then every time after, you loose one because you can't put the same book in the group twice.
10 * 9 * 8 * 7 = 5040 groups
Answer:
= 2(2x + 5)
Step-by-step explanation:
Given that:
= (7x + 5) - (3x - 5)
By simplifying
"-" sign before bracket will alter the inner signs
= 7x + 5 - 3x + 5
Adding like terms
= 4x + 10
By taking 2 common we get:
= 2(2x + 5)
i hope it will help you!