[radicals][section 58]
       __
(1.)  √16            here is the problem

=      4               take the square root of 16
       __
(2.)  √49             here is the problem

=    7           take the square root of 49
        ___
(3.)  -√144            here is the problem

=    -12            take the square root of 144
        __
(4.)  -√81             here is the problem

=    -9                take the square root of 81
       ____
(5.)  √1002               here is the problem

=     100              cancel
         __
(6.)   (√13)2           here is the problem

=       13             cancel
        ____
(7.)   √64c6             here is the problem

=     8c3           take the square root of 64c6
         _____
(8.)   -√4x2y2           here is the problem

=    -2xy          take the square root of 4x2y2
         ____
(9.)    √2.25        here is the problem

=      1.5           take the square root of 2.25
         ____
(10.)   √r12t6          here is the problem

=     r6t3        take the square root of r12t6