Question

раскройте скобки и привидите подобные слагаемые 1) 1/21*(7a - 3/7b)+1/49*(b-2/3a) 2)1 2/3 *(-21a-2/25a)+4/5a+b 3) -3 1/8*(2/25c-4/5)+1/4c-1/2 4)-1/2a*(1/3b-1/4)-2/3ab
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Answer 1

1)1/21*(7a - 3/7b)+1/49*(b-2/3a)

= (7a/21 - 3b/147) + (b/49 - 2a/147)

= (7a - 3b)/21 + (b - 2a)/49

2)1 2/3 *(-21a-2/25a)+4/5a+b

= (-21a - 2a/25) + (4/5)a + b

= (-23a - 2a/25) + (4/5)a + b

= (-23/25)a + (4/5)a + b

= (-23a/25 + 4a/5) + b

3)-3 1/8*(2/25c-4/5)+1/4c-1/2

= (-3/8)(2/25c - 4/5) + (1/4)c - 1/2

= (-6/25c + 3/5) + (1/4)c - 1/2

= (-6/25c + 1/4c + 3/5) - 1/2

= (-6c/25 + c/4 + 3/5) - 1/2

= (-6c/25 + c/4 - 1/2) + 3/5

4)-1/2a*(1/3b-1/4)-2/3ab

= (-1/2a)(1/3b - 1/4) - (2/3)ab

= (-1/6b + 1/8a) - (2/3)ab

= (-1/6b - 2ab/3) + (1/8a)

= (-1/6b - 2ab/3 + 1/8a)