F you just want to see the really short way, just skip down to AAAAAAAAAAAA
so, here is the long explanation
exponential properties

don't forget pemdas
2x^2=2(x^2)
so

=

AAAAAAAAAAAAAAAAAAAAAAAA
so we see
the original equatio is

remember

so we can seperate the constants

we know that the placeholders cannot affet the position of the constants unless they are grouped together which they are not
terfor the answer must have 2/3 in it
the only one that hsa that is A
ANSWER IS A
Setting it up, we have Dan + Bret + Maria all saving 600.00
Dan = 2B
Bret = B
Maria = B+60
2B + B + B + 60 = 600
4B = 540
B = 135
Dan = 2(135) = 270
Brett = 135
Maria = 135 + 60 = 195
Every whole number is a rational number because whole numbers can be written as fractions.
For #8, it's approximately 2.5