Which is the best estimate for (6.3x 10^-2)(9.9x 10^-3) written in scientific notation? A. 6x10^-4 B. 60 x 10^-5
C. 6x 10^7
D. 60 x 10^6

Tanya has $42 to spend at the dolphin island store. tshirts sell for $7 each and a pair of sunglases sells for $6.tanya buys 3 tshirts. how many pairs of sunglases can she buys with the amount of money she has left

How to do this , and can some one explain

When is g(x) = 0 for the function g(x) = 5.23x + 4?