6-9-2-25

Rewrite -9 as -1(9).

6-1(9)-2-25

Rewrite -1(9) as -1⋅9.

6(-1⋅9)-2-25

Rewrite -1 as i.

6(i⋅9)-2-25

Rewrite 9 as 32.

6(i⋅32)-2-25

Pull terms out from under the radical, assuming positive real numbers.

6(i⋅3)-2-25

Move 3 to the left of i.

6(3⋅i)-2-25

Multiply 3 by 6.

18i-2-25

Rewrite -25 as -1(25).

18i-2-1(25)

Rewrite -1(25) as -1⋅25.

18i-2(-1⋅25)

Rewrite -1 as i.

18i-2(i⋅25)

Rewrite 25 as 52.

18i-2(i⋅52)

Pull terms out from under the radical, assuming positive real numbers.

18i-2(i⋅5)

Move 5 to the left of i.

18i-2(5⋅i)

Multiply 5 by -2.

18i-10i

18i-10i

Subtract 10i from 18i.

8i

Simplify 6 square root of -9-2 square root of -25