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Solve using the Quadratic Formula:

a) -7x^2 + 7x + 1 = -8

b) -6x - 1 + 5x^2 = 8x^2

Show your work.

User Jstricker
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1 Answer

3 votes

A. - 7x² + 7x + 1 + 8 = 0

- 7x² + 7x + 9 = 0

x = - b ± √b² - 4ac / 2a

= - 7 ± √7² - 4 (-7) (9) / 2 (-7)

= - 7 ± √49 + 252 / - 14

= - 7 ± √ 301 / - 14

x = - 7 + 17.349 / - 14 x = - 7 - 17.349 / - 14

= 10.349 / - 14 = - 24.349 / - 14

= - 0.739 = - 1.739

B. 8x² - 5x² + 6x + 1 = 0

3x² + 6x + 1 = 0

x = - b ± √b² - 4ac / 2a

= - (-5) ± √-5² - 4 (3) (1) / 2 (3)

= 5 ± √25 - 12 / 6

= 5 ± √ 13 / 6

x = 5 + 3.606 /6 x = - 5 - 3.606 / 6

= 8.606/6 = - 8.606/6

= 1.434. = - 1.434

please re-check the answers hope this helps

User Matox
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