Question

1.Раскройте скобки и упростите выражение: 1)-(a-b)-b; 2)-c+(c-d); 3)-(2,7-a)+(-a+1,8); 4)-(-6,2+a+b)-(a-b+10,9). 2.Приведите подобные слагаемые: 1) -4а+12а+13а-27а; 2)4,2х-4,8х-6,3х-2,4х; 3)-17х+19у-15у+13х; 4)0,9n-0,8m-0,7m+3,5n-1,9n.

Answer 1

№ 1
1) -(a - b) - b = -a + b - b = -a
2) -c + (c - d) = -c + c - d = -d
3) -(2,7 - a) + (-a + 1,8) = -2,7 + a - a + 1,8 = -0,9
4) -(-6,2 + a + b) - (a - b + 10,9) = 6,2 - a - b - a + b - 10,9 = -2a - 4,7

№ 2
1) -4а + 12а + 13а - 27а = -6а
2) 4,2х - 4,8х - 6,3х - 2,4х = -9,3
3) -17х + 19у - 15у + 13х = -4х + 4у
4) 0,9n - 0,8m - 0,7m + 3,5n - 1,9n = 2,5n - 1,5 m

Answer 2

1. Раскройте скобки и упростите выражение: 1) (1) - (a - b) - b

To simplify this expression, let's first remove the parentheses:

1 - a + b - b

Next, we can combine like terms by combining the variables with the same exponent:

1 - a + b - b = 1 - a

Therefore, the simplified expression is 1 - a.

2) -c + (c - d)

Remove the parentheses:

-c + c - d

Combine like terms:

-c + c - d = -d

The simplified expression is -d.

3) (2.7 - a) + (-a + 1.8)

Remove the parentheses:

2.7 - a - a + 1.8

Combine like terms:

2.7 - a - a + 1.8 = 2.7 - 2a + 1.8

The simplified expression is 2.7 - 2a + 1.8.

4) -(-6.2 + a + b) - (a - b + 10.9)

Remove the parentheses:

-(-6.2 + a + b) - a + b - 10.9

Combine like terms:

-(-6.2 + a + b) - a + b - 10.9 = 6.2 - a - b - a + b - 10.9

The variables cancel out:

6.2 - a - b - a + b - 10.9 = 6.2 - 10.9

Combine the constants:

6.2 - 10.9 = -4.7

The simplified expression is -4.7.

2. Приведите подобные слагаемые: 1) -4a + 12a + 13a - 27a

Combine like terms by adding or subtracting the coefficients of the same variable:

-4a + 12a + 13a - 27a = (-4 + 12 + 13 - 27) a

Add the coefficients:

(-4 + 12 + 13 - 27) = -6

The simplified expression is -6a.

2) 4.2x - 4.8x - 6.3x - 2.4x

Combine like terms:

4.2x - 4.8x - 6.3x - 2.4x = (4.2 - 4.8 - 6.3 - 2.4) x

Add the coefficients:

(4.2 - 4.8 - 6.3 - 2.4) = -9.3

The simplified expression is -9.3x.

3) -17x + 19y - 15y + 13x

Combine like terms:

-17x + 19y - 15y + 13x = (-17 + 13) x + (19 - 15) y

Add the coefficients:

(-17 + 13) = -4

(19 - 15) = 4

The simplified expression is -4x + 4y.

4) 0.9n - 0.8m - 0.7m + 3.5n - 1.9n

Combine like terms:

0.9n - 0.8m - 0.7m + 3.5n - 1.9n = (0.9 + 3.5 - 1.9) n + (-0.8 - 0.7) m

Add the coefficients:

(0.9 + 3.5 - 1.9) = 2.5

(-0.8 - 0.7) = -1.5

The simplified expression is 2.5n - 1.5m.