(3а+6)/5 - (а-7)/4 = 1 | * 4*5
4(3a+6) - 5(a-7) = 1*4*5
12a + 24 - 5a +35 = 20
7a + 59 = 20
7a = 20 - 59
7a = -39
a= - 39/7
a= -5 4/7
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( 3 * ( - 5 4/7 ) + 6 )/5 - ( - 5 4/7 - 7)/4 = 1
(- 16 5/7 + 6)/5 - ( - 12 4/7) / 4 = 1
(-10 5/7) * 1/5 - (- 88/7 ) * 1/4 = 1
(- 75/7 ) * 1/5 - (-22/7) = 1
-15/7 + 22/7 = 1
7/7 = 1
1 = 1
(2/7 - 1/14) - (3.5 - 17.5) =
= (4/14 - 1/14) - (- 14) =
= 3/14 + 14 =
= 14 3/14
(2/7 + 3/14) * (7.5 -13.5) =
= ( 4/14 + 3/14) * (-6) =
= 7/14 * (-6) =
= 1/2 * (- 6/1) =
= - 6/2 = - 3
( 2 - (6 5/8 - 7 1/3) ) / 1.25 =
= ( 2 - ( 6 15/24 - 7 8/24)) / 1.25=
= ( 2 - ( - 17/24)) / 1.25=
= 2 17/24 : (125/100) =
= 65/24 : 5/4 =
= 65/24 * 4/5 = 13/6 =
= 2 1/6