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)?​

Answer 1

Ответ:

1, 2, 4, 5 --  дұрыс

3, 6 -- қате

Объяснение:

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

Answer 2

1. 3a(5b) = 15ab is correct. When you multiply 3a by 5b, you get 15ab.

2. 1 + (x - y) = 1 - (y - x) is incorrect. Let's simplify both sides of the equation to see if they are equal: On the left side: 1 + (x - y) = 1 + x - y. On the right side: 1 - (y - x) = 1 - y + x. As we can see, the signs in the parentheses are distributed differently on both sides. Therefore, the equation is not correct.

3. 2a + (3b - 4) = 2a - (3b + 4) is correct. When you add 2a to (3b - 4), it is equivalent to subtracting (3b + 4) from 2a.

4. a - (4b - c) = a - 4b + c is correct. When you subtract (4b - c) from a, it is equivalent to subtracting 4b and adding c to a.

5. (-1) * b + a = a - b is correct. When you multiply -1 by b and add a, it is equivalent to subtracting b from a.

6. 5a - 17 = 5(a - 17) is correct. When you multiply 5 by (a - 17), it is equivalent to multiplying 5 by a and subtracting 17 from it.