I don’t get this how do these things work please explain

What is the simplified form of 7 √x • 7 √x • 7 √x • 7 √x?

The circumference of a redwood tree trunk is 20π ft, and it is 100 ft tall. what is the approximate volume of the redwood tree trunk? 1,000π ft3 10,000π ft3 4,000π ft3 40,000π ft3

Jonah buys a television that costs $445. sales tax in his state is 7 percent. which of the following expressions represent the amount of tax on the television?