The diameter of a certain bacterium is about 0.0000004 how you write this in scientific notation

Im literally having a mental breakdown

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /

10 points? ? +++ me asap gabriella uses the current exchange rate to write the function, h(x), where x is the number of u.s. dollars and h(x) is the number of euros, the european union currency. she checks the rate and finds that h(100) = 7.5. which statement best describes what h(100) = 75 signifies? a) gabriella averages 7.5 u.s. dollars for every 100 euros. b) gabriella averages 100 u.s. dollars for every 25 euros. c) gabriella can exchange 75 u.s. dollars for 100 euros. d) gabriella can exchange 100 u.s. dollars for 75 euros.