= 21/17*(2+2/3-3/4)+(17+11/12)*21/17
=21/17*(2+2/3-3/4+17+11/12)
=21/17*(2+8/12-9/12+17+11/12)
=21/17(2-1/12+17+11/12)
=21/17(2+17+10/12)
=21/17(19+5/6)
=21/17*119/6
=(3*7/17)*(17*7/3*2)
=49/2
= 21/17*(2+2/3-3/4)+(17+11/12)*21/17
=21/17*(2+2/3-3/4+17+11/12)
=21/17*(2+8/12-9/12+17+11/12)
=21/17(2-1/12+17+11/12)
=21/17(2+17+10/12)
=21/17(19+5/6)
=21/17*119/6
=(3*7/17)*(17*7/3*2)
=49/2