X^2 + (3x-9) ^2 = (2x+1) ^2

Question

Chaz Rowland

Mathematics

14 June, 06:47

X^2 + (3x-9) ^2 = (2x+1) ^2

+4

Answers (1)

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Shaun · Answer 1

x² + (3x - 9) ² = (2x + 1) ²

x² + (3x - 9) (3x - 9) = (2x + 1) (2x + 1)

x² + (9x² - 27x - 27x + 81) = (4x² + 2x + 2x + 1)

x² + (9x² - 54x + 81) = 4x² + 4x + 1

(x² + 9x²) - 54x + 81 = 4x² + 4x + 1

10x² - 54x + 81 = 4x² + 4x + 1

- 4x² - 4x²

6x² - 54x + 81 = 4x + 1

+ 54x + 54x

6x² + 81 = 58x + 1

- 1 - 1

6x² + 80 = 58x

6x² - 58x + 80 = 0

x = - (-58) + / - √ ((-58) ² - 4 (6) (80)

2 (6)

x = 58 + / - √ (3364 - 1920)

12

x = 58 + / - √ (1444)

12

x = 58 + / - 38

12

x = 58 + 38 x = 58 - 38

12 12

x = 96 x = 20

12 12

x = 6 x ≈ 1.67