Question

Даю 50 баллов.Решите уравнение: 1) 7х = -30 + 2х; 5) 0,2х + 4,3 = 0,4х - 6,5; 2) 16 - 18х = -25x - 12; 6) 0,6х + 100 = 0,9x + 1; 3) -17х + 20 = 7х - 28; 7) -9/14 х + 18 =-2/3 х + 17; 4) 20 - 2х = 27 + х; 8) -8/15 х -11 = 4/9 х + 11.

Answer 1

1) 7х = -30 + 2х; 
7х - 2x = - 30 
5x = - 30 
x = - 6 
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5) 0,2х + 4,3 = 0,4х - 6,5; 
0,4x - 0,2x = 4,3 + 6,5 
0,2x = 10,8
x = 54
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2) 16 - 18х = -25x - 12; 
25x - 18x = - 12 - 16 
7x = - 28 
x = - 4 
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6) 0,6х + 100 = 0,9x + 1; 
0,9x - 0,6x = 100 - 1 
0,3x = 99
x = 330 
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3) -17х + 20 = 7х - 28; 
7x + 17x = 20 + 28 
24x = 48 
x = 2 
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7) -9/14 х + 18 =-2/3 х + 17; 
- 9/14x + 2/3x = 17 - 18 
- 27/42x + 28/42x = - 1 
1/42x = - 1 
x = - 42 
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4) 20 - 2х = 27 + х; 
x + 2x = 20 - 27 
3x = - 7 
x = - 7/3 
x = - 2 1/3 
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8) -8/15 х -11 = 4/9 х + 11.
- 8/15x - 4/9x = 11 + 11
- 24/45x - 20/45x = 22 
- 44/45x = 22 
x = 22 : ( - 44/45 )
x = - 45/2 
x = - 22 1/2 

Answer 2

1)7х-2х=-305х=-30х=-62)-18х+25х=-16-127х=-28х=-43)-17х-7х=-20-28-24х=-48х=25)0,2х-0,4х=-4,3-6,5-0,2=-10,8х=546)0,6х-0,9х=-100+1-0,3х=-99х=3307)-9/14х+2/3х=-18+17-27/42х+28/42х=-11/42х=-1х=-428)-8/15х-4/9х=11+11-24/45х-20/45х=22-44/45х=22х=-22,5задание 21)3х+х=28 2)5х-8х=-12+304х=28 -3х=-18х=7 х=63)8х+5х=-33+72 4)6х+х=19-1013х=39 7х=9х=3 х=9/75)-0,2х-0,3х=-0,7-1,8-0,5х=-2,5х=5

Answer 3

Sure, I'd be happy to help you solve these equations. Let's go through each one step by step:

1. 7x = -30 + 2x

Subtract 2x from both sides: 7x - 2x = -30

Combine like terms: 5x = -30

Divide both sides by 5 to isolate x: x = -30 / 5 x = -6

2. 16 - 18x = -25x - 12

Add 25x to both sides: 16 + 7x = -12

Subtract 16 from both sides: 7x = -12 - 16 7x = -28

Divide both sides by 7 to isolate x: x = -28 / 7 x = -4

3. -17x + 20 = 7x - 28

Add 17x to both sides: 20 = 7x + 17x - 28

Combine like terms: 20 = 24x - 28

Add 28 to both sides: 48 = 24x

Divide both sides by 24 to isolate x: x = 48 / 24 x = 2

4. 20 - 2x = 27 + x

Add 2x to both sides: 20 = 27 + x + 2x

Combine like terms: 20 = 27 + 3x

Subtract 27 from both sides: -7 = 3x

Divide both sides by 3 to isolate x: x = -7 / 3

5. 0.2x + 4.3 = 0.4x - 6.5

Subtract 0.2x from both sides: 4.3 = 0.4x - 0.2x - 6.5

Combine like terms: 4.3 = 0.2x - 6.5

Add 6.5 to both sides: 10.8 = 0.2x

Divide both sides by 0.2 to isolate x: x = 10.8 / 0.2 x = 54

6. 0.6x + 100 = 0.9x + 1

Subtract 0.6x from both sides: 100 = 0.9x - 0.6x + 1

Combine like terms: 100 = 0.3x + 1

Subtract 1 from both sides: 99 = 0.3x

Divide both sides by 0.3 to isolate x: x = 99 / 0.3 x = 330

7. -9/14x + 18 = -2/3x + 17

Add 2/3x to both sides: -9/14x + 2/3x + 18 = 17

To get rid of fractions, let's find a common denominator. The least common multiple of 14 and 3 is 42.

Multiply the entire equation by 42 to eliminate the denominators: 42 * (-9/14x) + 42 * (2/3x) + 42 * 18 = 42 * 17

Simplify: -27x + 28x + 756 = 714

Combine like terms: x + 756 = 714

Subtract 756 from both sides: x = 714 - 756 x = -42

8. -8/15x - 11 = 4/9x + 11

Add 8/15x to both sides: -11 + 8/15x = 4/9x + 11

To get rid of fractions, let's find a common denominator. The least common multiple of 15 and 9 is 45.

Multiply the entire equation by 45 to eliminate the denominators: 45 * (-11) + 45 * (8/15x) = 45 * (4/9x) + 45 * 11

Simplify: -495 + 24x = 20x + 495

Subtract 20x from both sides: 4x = 990

Divide both sides by 4 to isolate x: x = 990 / 4 x = 247.5

So, the solutions for each equation are:

1. x = -6
2. x = -4
3. x = 2
4. x = -7/3 (approximately -2.333)
5. x = 54
6. x = 330
7. x = -42
8. x = 247.5