Pls help with the last two

Complex numbers multiply √-4 * √-25 and show all intermediate steps. alternative notation is sqrt(-4) * sqrt(-25).

What is the common difference for this arithmetic sequence? -6,-2,2,6,10 a.4 b.5 c.3 d.6

The length of a rectangular plot of land is given by the expression 6x^3y^4. the width of the plot is given by the expression 5x^5y^4z. find an expression to represent the area of the rectangular plot.