Pure gold and silver have densities of 19,300 kg/m^3 and 10,500 kg/m^3, respectively. If a jeweler uses 0.25 cm^3 of metal to make a ring then how much heavier (in grams) is the gold ring compared to the silver ring?

Find dy/dx using implicit differentiation ln(20+e^xy)=y

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

Which expression is the factorization of x^2+10+21