Which line contains the point (2, 1)?
a)4x-y=7
b)2x+5y=4
c)7x-y=15
d)x+5y=21

One dollar bills size is 2.61 squared inches
and 1 squared inch equals 0.00064516 meter
one trillion is: 1,000,000,000,000,000,000
So the size of the dollar bill in meters is:
(2.61)(0.00064516) = 0.0016 squared meters
therefore the area covered by the dollar bills is:
1,000,000,000,000,000,000*0.0016
= 1.6 x 10^15 square meters
that is scientific notation (1.6 followed by 15 zeroes)