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Solve: -6x-1+5x^2=8x^2

1 Answer

4 votes

Answer:


x_(1) = -1 - \sqrt{(2)/(3)}  ; x_(2) = -1 +\sqrt{(2)/(3)}

Explanation:

-6x -1 + 5x² = 8x² Move all terms to the right-hand side

0 = 8x² - 5x² + 6x +1 Combine like terms

3x² + 6x + 1 = 0

Apply the quadratic formula


x = (-b\pm√(b^2-4ac))/(2a)

a = 3; b = 6; y = 1


x = (-6\pm√(6^2 - 4* 3 *1))/(2* 3)


x = (-6\pm√(36-12))/(6)


x = (-6\pm√(24))/(6)


x = (-6\pm √(4*6))/(6)


x = (-6\pm 2√(2))/(6)


x = -1 \pm \sqrt{(2)/(3)}


x_(1) = -1 +\sqrt{\frac{{2}}{3}}; x_(2) = 1 -\sqrt{\frac{{2}}{3}}

The graph below shows the roots at x₁ =-1.816 and x₂ = -0.184.

Solve: -6x-1+5x^2=8x^2-example-1
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