Question

помогите пожалуйста решить ​

Answer 1

Ответ:

7.3.

1) x = 67

2) x = (5 + 20 ∛7) / 18

3) x = 2

7.6.

1) x = 1

2) x = 2

3) x = 2 or x = -1

4) x = 2 or x = -5/2

5) x = 9

6) x = (3 + sqrt(193)) / 27.8.

1) x = 3 or x = 4

2) x = 9/2 or x = 5

7.10.

1) y = root(x, 3), then y^2 - 2y - 3 = 0, y = 3 or y = -1. Therefore, x = 27 or x = -1.

2) y = sqrt(x), then y^4 - y^2 - 36 = 0, y = √5 or y = -√5. Therefore, x = 5 or x has no solution.

3) Let y = sqrt(x), then y^4 - 7y^2 - 15 = 0, (y^2 - 15)(y^2 + 1) = 0. Therefore, y = √15 or y = -√15 (not a solution) and x = 15.

4) Let y = sqrt(x+1), then (2y-1)^2 = 12y, y = 4 or y = 1/3. Therefore, x = 15 or x = 8/9.

5) Let y = root(x, 4), then (1/y - 1)^3 - 3(1/y - 1) - 2 = 0, y = 3 or y = 1/2. Therefore, x = 81 or x = 16.