Question

Мына теңбе-теңдіктер дұрыс па:

• 1) 3а(5b) = 15аb;

• 2) 1+(x – y) = 1 – (y – x ) ;

• 3) 2a+(3 b – 4 ) = 2a – (3b+4)?

• 4) а – (4b – с) = a – 4b + c;

• 5) (-1) • b+а = а – b;

• 6) 5а – 17 = 5(а – 17)?

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Answer 1

Ответ:

1, 2, 4, 5 --  дұрыс

3, 6 -- қате

Объяснение:

$1) 3a(5b) = 15ab\\ 15ab = 15ab\\\\2) 1 + (x - y) = 1 - (y - x)\\ 1 + x - y = 1 - y + x\\ x - y = -y + x\\ x - y = x - y\\\\3)2a + (3b - 4) = 2a - (3b + 4)\\ 2a + 3b - 4 = 2a - 3b - 4\\ 3b - 4 = -3b -4\\ 3b \neq -3b\\\\4) a - (4b - c) = a - 4b + c\\ a - 4b + c = a - 4b + c\\\\5) (-1) * b + a = a - b\\-b = -b\\\\6) 5a - 17 = 5(a - 17)\\5a - 17 = 5a - 85\\17 \neq 85$