Simplifica las siguientes expresiones algebraicas: 1.- 2x3 - 7x2 + 5x - 2 - 8x3 + 9x2 - 3x + 13=
2.- 5m3 - 9n3 + 6m2n - 8mn2 - 14mn2 + 21m2n - 5m3 + 18=
3.- -a5b + 6a3b3 - 18ab5 + 42 + 8a2 - 11a4b2 + 11a2b=
4.- mn + 1 - 6mn - 2 + 8mn - 3 - 19mn - 5 - 8mn - 5mn - 2 - 6mn - 3 - mn - 4 - 9mn - 5=
5.- -7x2 + 5x - 3 + 4x2 - 2x + 4 + 5x2 - x=

Look i don’t know the answer to this but someone else will so just wait a little bit longer

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