1). 1/3x + 1/5x + 1/6x = 21/40 2).1/4x + 1/6x + 1/8x = 39/56

Question

1). 1/3x + 1/5x + 1/6x = 21/40
2).1/4x + 1/6x + 1/8x = 39/56

Answer 1

Это первое,сейчас решу и второе) 2)1/4x+1/6x+1/8x=39/56 42/168x+28/168x+21/168x=117/168 91/168x=117/168 x=117/168*168/91 x=117/92 x=1целая 26/91

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Answer 2

1) (10+6+5)/30x=21/40
21/30x=21/40
30x=(40*21)/21
30x=40
x=40/30
x=4/3