Simplify 1)  root 45 - 3 root 20 +4 root 5 plzz write the sum

= root 45 - 3 root 20 + 4 root 5
= root 9 * root 5 - 3 * root 4 * root 5 + 4 root 5
=3 root 5 - 3 * 2 * root 5 + 4 root 5
= root 5 ( 3 - 6 + 4 )
= root 5 *1
= root 5

Best answer that i found on yahoo ok   set :   x= length of 2nd piece in cm  x- 3= length of 1st piece in cm  x-4= length of 3rd piece in cm  then since you know they all came from the 20 cm ribbon you add them together and set them equal to 20x+ x-3 +x-4 = 20  3x - 7= 20  3x= 27  x= 9  the shortest piece is the third piece which is x- 4  x-4  9-4 = 5  the length of the smallest piece is 5 cm.  the other lengths are  9 cm  6 cm