Question

463. Решите уравнение: 1) 3/5 x + 2/15 x = 10 2) (2/3 + 5/7 x ) × 21 =293) 4 1/3 x - 2 2/3 x =5 ​

Answer 1

1) 3/5 x + 2/15 x = 10

3/5 + 2/15 * x

(9/15 + 2/15)х = 11/15х

11/15 * x = 10/1

10/1 * 15/11 = x

x = 150/11

2)  (2/3 + 5/7 x ) × 21 = 29

2/3 * 21/1 = 14

5/7x * 21/1 = 15x

14+15x=29

15x=15

x=1

3) 4 1/3 x - 2 2/3 x = 5 ​

(13/3 - 8/3)х = 5/3х

5/3 * x = 5/1

x = 3

Answer 2

1) 3/5 + x + 2/15 + x = 10 3/5 + 2/15 + 2x = 10 Multiplying all terms by 15 to get rid of the fractions: 9 + 2 + 30x = 150 30x = 150 - 11 30x = 139 x = 139/30

2) (2/3 + 5/7 + x) * 21 = 29 21(2/3 + 5/7 + x) = 29 Multiplying all terms by 21 to get rid of the fraction: 14 + 15 + 21x = 29 29 + 21x = 29 21x = 29 - 29 21x = 0 x = 0

3) 4 1/3 + x - 2 2/3 + x = 5 13/3 + x - 8/3 + x = 5 5x + 5 = 5 5x = 5 - 5 5x = 0 x = 0

So the solutions to the equations are: 1) x = 139/30 2) x = 0 3) x = 0