Пошаговое объяснение:
/ - это дробь —
1
(2/7+3 1/2)×4 2/3=(3+(4/14+7/14))×4 2/3=
=(3+ 11/14)×14/3=3 11/14×14/3=53/14×14/3=
=53/3=17 2/3
2
(4 1/5-2 3/4)×2 2/19=
=((4-2)+(4/20-15/20))×2 2/19=
=(2+(-11/20))×40/19=((40-11)/20)×40/19=
=29/20×40/19=58/19=3 1/19
3
(5 6/7+3 5/21)×2 1/10=
=((5+3)+(18/21+5/21))×21/10=
=(8+23/21)×21/10=8 23/21×21/10=
=191/21×21/10=191/10=19 1/10
4
(7 5/12-3 1/6)×2 2/17=
=((7-3)+(5/12-2/12))×36/17=
=(4+3/12)×36/17=4 1/4×36/17=
=17/4×36/17=9
Пошаговое объяснение:
/ - это дробь —
1
(2/7+3 1/2)×4 2/3=(3+(4/14+7/14))×4 2/3=
=(3+ 11/14)×14/3=3 11/14×14/3=53/14×14/3=
=53/3=17 2/3
2
(4 1/5-2 3/4)×2 2/19=
=((4-2)+(4/20-15/20))×2 2/19=
=(2+(-11/20))×40/19=((40-11)/20)×40/19=
=29/20×40/19=58/19=3 1/19
3
(5 6/7+3 5/21)×2 1/10=
=((5+3)+(18/21+5/21))×21/10=
=(8+23/21)×21/10=8 23/21×21/10=
=191/21×21/10=191/10=19 1/10
4
(7 5/12-3 1/6)×2 2/17=
=((7-3)+(5/12-2/12))×36/17=
=(4+3/12)×36/17=4 1/4×36/17=
=17/4×36/17=9