What is the square root of -1

What is the rate of change of a line that passes through (2,-5) and (6,-2)?

Jamie went to home depot.she bought 25 bags of soil that cost $9 per bag.she bought 15 pots at $8 each,and she bought 23 bags of pebbles at $15 each.she used a coupon that gave her $5 off for every 100 dollars she spent.how much did jame pay at the end?

What is the approximate value of  x  in the equation below.–3.396–0.7080.3040.955