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Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth.

x^2 - 8 = -6x

a. –7.12, 1.12
b. 7.12, –1.12
c. 7.12, 1.12
d. –7.12, –1.12

Respuesta :

SaniShahbaz

Answer:

x = -7.12, 1.12

Step-by-step explanation:

We are given an equation and asked to solve it with quadratic formula

Quadratic formula is given as:

[tex]x = \frac{-b +- \sqrt{b^{2}-4ac } }{2a}[/tex]

Given equation: x² - 8 = -6x

Rewriting the equation

x² - 8 + 6x = 0

x² + 6x - 8 = 0

Where a = 1; b = 6; c = -8

Putting the values of a, b and c in quadratic formula

[tex]x = \frac{-6 +- \sqrt{6^{2}-4(1)(-8) } }{2(1)}[/tex]

[tex]x = \frac{-6 +- \sqrt{36+32}}{2}[/tex]

[tex]x = \frac{-6 +- \sqrt{68}}{2}[/tex]

[tex]x = \frac{-6 +- 8.25}{2}[/tex]

[tex]x = \frac{-6 + 8.25}{2}[/tex]

      x = 1.12

[tex]x = \frac{-6 - 8.25}{2}[/tex]

      x = -7.12


x = -7.12, 1.12

alinakincsem

Answer:

The correct answer option is a. –7.12, 1.12.

Step-by-step explanation:

We are given the following equation and we are to solve it using the quadratic formula:

[tex]x^2 - 8 = -6x[/tex]

Re-arranging this equation in order of decreasing power:

[tex] x^{2} + 6x - 8 = 0 [/tex]

Using the quadratic formula:

[tex] x = \frac {-b + - \sqrt{b^2 - 4ac} }{2a}[/tex]

Substituting the given values in the formula to get:

[tex]x=\frac{-6+-\sqrt{(6)^2-4(1)(-8)} }{2(1)}[/tex]

[tex]x=\frac{-6+-\sqrt{68} }{2}[/tex]

[tex]x=\frac{-6+\sqrt{68} }{2} , x= \frac{-6-\sqrt{68} }{2}[/tex]

[tex]x=1.12, x=-7.12[/tex]

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