You can then write really big numbers without running out of space
for example instead of 2300000000000000000000000000
you can just write 2.3 x 10^27
I think the common denominator is 90. 8,9,and 10 can all go into 90.
(7x+2)(20-3x/4) = 140x + 40 - 21x²/4 - 3x/2 = -21/4 x² + 138 1/2 x + 40
this is one of those multiplications that doesn't make the result look any simpler...
P=2*(l+w)
p=2l+2w
2w=p - 2l
w= (p-2l)/2
