-3(b - 7)
Distributive property
-3*b = -3b
-3*7 = -21
-3b + 21
Answer: -3b + 21
Vlad did not make a mistake.
25 = 5*5 and 9 = 3*3, which we can exploit to write

so that this expression is actually a difference of squares. We can factorize this to get

and given that
, we divide both sides by this to get

Answer:
what do I have to do???........
She gave Diana, her sister, 6 stickers. This is because 41 divided by 7 is 5 R 6 and there are 6 stickers left if you want each group to have the same amount with no leftovers.