Question

Please answer the question it is very important for me​

Answer 1

Answer:

x+(y+z)=(x+y)+z

2/3+(2/7+-1/5)=(2/3+2/7)+-1/5

2/3+(10-7/35)=(14+6/21)+-1/5

2/3+(3/35)=(20/21)+-1/5

2/3+3/35=20/21+-1/5

70+9/105=100-21/105

79/105=79/105