Question

Раскройте скобки (x-y)+(y-3b) -(a-b)+(-x+a)-(b-x) -(x-9)+(a-5) (a-7)-(5+a)-(9-a) (x-a)+(y+b) -(m+n)+(n-p)-(-p-m) (b-4)-(-c+7) (-m+8)-(m-4)+(-8+m)

Answer 1

(x-y)+(y-3b) = x-y+y-3b = x-3b
-(a-b)+(-x+a)-(b-x) = -a+b-x+a-b+x=0
-(x-9)+(a-5) = -x+9+a-5 = a-x+4
(a-7)-(5+a)-(9-a) = a-7-5-a-9+a = a - 21
(x-a)+(y+b) = x-a+y+b
-(m+n)+(n-p)-(-p-m) = -m-n+m-p+p+m = m-n
(b-4)-(-c+7) = b-4+c-7 = b+c-11
(-m+8)-(m-4)+(-8+m) = -m+8-m+4-8+m = 4-m

Answer 2

Раскроем скобки и упростим выражение:

1. (x - y) + (y - 3b) - (a - b) + (-x + a) - (b - x) - (x - 9) + (a - 5) = x - y + y - 3b - a + b + x - a + b - x - x + 9 + a - 5 = (x - x - x) + (y + y) + (b - 3b + b) + (a - a + a) + (b - b) + (9 - 5) = 0 + 2y - b + 2a + 0 + 4 = 2y - b + 2a + 4

2. (a - 7) - (5 + a) - (9 - a) = a - 7 - 5 - a - 9 + a = (a - a - a) - 7 - 5 - 9 - 7 = 0 - 21 = -21

3. (x - a) + (y + b) - (m + n) + (n - p) - (-p - m) = x - a + y + b - m - n + n - p + p + m = x - a + y + b - m + m - n + n + p - p = x - a + y + b (Условие (-m + m) и (-p + p) дают ноль, а (-n + n) дают также ноль.)

4. (b - 4) - (-c + 7) = b - 4 + c - 7 = b + c - 4 - 7 = b + c - 11

5. (-m + 8) - (m - 4) + (-8 + m) = -m + 8 - m + 4 - 8 + m = (-m - m + m) + (8 + 4 - 8) = 0 + 4 = 4

Таким образом:

1. (x - y) + (y - 3b) - (a - b) + (-x + a) - (b - x) - (x - 9) + (a - 5) = 2y - b + 2a + 4
2. (a - 7) - (5 + a) - (9 - a) = -21
3. (x - a) + (y + b) - (m + n) + (n - p) - (-p - m) = x - a + y + b
4. (b - 4) - (-c + 7) = b + c - 11
5. (-m + 8) - (m - 4) + (-8 + m) = 4