Question

b, c și d
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Answer 1

b)   ( - 1 / 18 + 1 / 12 ) × ( - 5 / 6 ) =

= ( - 2 / 36 + 3 / 36 ) × ( - 5 / 6 ) =

= 1 / 36 ×  ( - 5 / 6 ) =

= - 5 / 216

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c) 1 intreg si 1 / 2 = ( 1 x 2 + 1 ) / 2 = 3 / 2

( - 7 / 39  + 11 / 13 ) × ( - 3 / 2 ) =

= ( - 7 / 39 + 33 / 39 ) ×( -  3 / 2) =

= 26 / 39  × ( - 3 / 2 )=

= 2 / 3 ×( -  3 / 2)  =

= - 1

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d)  2 intregi si 1 / 5 = ( 2 x 5 + 1 ) / 5 = 11 / 5

( - 1 / 14 + 4 / 21 ) × 11 / 5 =

= ( - 3 / 42 + 8 / 42 ) × 11 / 5 =

= 5 / 42 × 11 / 5 =

= 11 / 42