Lizzy's new neckalce cost 0.4 cents less than lucy's neckalce that cost 0.29. cents.How many cents did lizzy's neckalce cost.
Answer:

perform cross multiplication:

The volumetric mean radius of Mars is about 3389.5 km. We know that it's 13.7% of Neptune's mean radius, so we can write it down as:
3389.5 = 13.7% of x (where x is Neptune's radius)
3389.5 = 13.7% x
3389.5 = 137/1000x / * 1000 (both sides)
3389500 = 137x / ÷ 137 (both sides)
x = 24740.87591240876
x ≈ 24740.88
Answer: The mean radius of Neptune is about 24740.88 km.
2.57*10^4 is 1,000,000 times more than 2.57*10^-1
Why?
4-(-1)=5 2
2.57*10^4=25700
2.57*10^-1=0.0257
and
25700
÷ 0.0257
=1000000
and 1000000=10^6
1) -2/2i
2) you divide the 2's
3) -1/i