Hewooo I'm bored wanna talkkk​

The experience c-0.25c can be used to find the cost of an item on sale for 25% off which expression beloit equivalent to c-0.25c

How many four digit even numbers can be formed from digits 1,2,3,4,5 if repetition is allowed. how can solve this using permutation formula

Which expression equals 9^3 sqrt 10 a. 5 sqrt 10 + 4 sqrt 10 b. 5^3 sqrt 10 + 4 ^3 sqrt 10 c. 5 sqrt 10 + 4^3 sqrt 10 d. 5^3 sqrt 10 + 4 sqrt 10