Simplify the expression.

√255

Step-by-step explanation:

If multiplication, just multiply root by root and number by number.

So, √15 . √17 = √255

Hope it helps and is useful :)

b. 2

step-by-step explanation:

the slope of a line =δy/δx

δy= y₂-y₁

δx= x₂-x₁

therefore, using the points (-2,-3)   and (3,7) we can calculate gradient as follows:

m=(7--3)/(3--2) (a number minus a negative number the sign changes to a plus)

m=(7+10)/(3+2)

=10/5

=2