The answer is -1
Byee.........?..
For these kinds of expressions use FOIL (first, outside, inside, last).
-2x • 9x = -18x^2
-2x • -3y = 6xy
8y • 9x = 72 xy
8y • -3y = -24y^2
Now combine them all:
-18x^2 + 78xy - 24y^2
One US-penny is 19 mm in diameter.
One British-penny is 20.3 in diameter.
We can make an accurate measurement of the diameters, or research on the internet.
1 milion US_pennies are
1,000,000*19 mm = 19,000,000 mm = 1,900,000 cm tall, since 1cm=10mm
1 milion British_pennies are
1,000,000*20.3 mm = 20,300,000 mm = 2,030,000 cm tall, since 1cm=10mm
