I'm not 100% sur what it is asking but I think the expression would be
15 min. * 10 = min. till the tank is full
The 10^-4 means that the decimal point is 4 places to the left of where it is in 8.25 (if the exponent was positive the decimal point would be to the right). If you move the decimal point 4 places to the left you get an answer of 0.000825 which is 8.25 * 10^-4 in standard form.
(-4,4) (3,-2)
formula for finding mid point is
M=(x1+x2/2,y1+y2/2)
m=-4+3/2,4-2/2
m=(-1/2,1)
- 28 - 40i
note that i² = (√-1)² = - 1
expand product of factors using FOIL
= - 6 - 6i - 14i - 14i² - 20i + 36i²
= - 6 - 6i - 14i + 14 - 20i - 36
= - 28 - 40i
