Need help on 2 questions If you dont know the answer please dont answer this is urgent. ( Includes Brainiest!)

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?

Solve x+3y=6 and 4x-6y=6 by elimination . show work !

Sketch the region enclosed by the given curves. decide whether to integrate with respect to x or y. draw a typical approximating rectangle and label its height and width. y= 5x, y=7x^2then find the area s of the region.