Please help with #3 & 4 for 15 points!!

Someone answer asap for ! the following statements are true about the coins calvin and sasha have collected. * calvin and sasha has the same amount of money. * calvin has only quarters. * sasha has dimes, nickels, and pennies * calvin has the same number of quarters as sasha has dimes. * sasha has $1.95 in coins that are not dimes. exactly how many quarters does calvin have?

X-10/4 when x = –18 a 7 b –2 c –7 d 2

What is 0.000008 meters in scientific notation