Respuesta :

znk

Answer:

x = -8.75; x = 7.25

Step-by-step explanation:

                                                         2(x + ¾)² - 5 = 123

  1. Add 5 to each side:                     2(x+ ¾)² = 128
  2. Divide each side by 2:                   (x+ ¾)² = 64
  3. Take the square root of each side: x + ¾ = 8       x + ¾ = -8
  4. Subtract ¾ from each side:                     x = 8 - ¾        x = -8 - ¾
  5. Convert to decimal fraction:                    x = 8 - 0.75    x = -8 – 0.75  
  6. Subtract:                                                   x = 7.25           x = -8.75

The graph of your equation is a parabola with x-intercepts at x = -8.75

and x = 7.25.


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The list of steps, in order, that will solve the equation is:

  • Addition of 5 to both sides to eliminate the value of -5
  • Division of both sides of the equation by 2 to eliminate the coefficient of 2 from the left-hand side
  • Taking the square root of both sides
  • subtract 3/4 from each side
  • Convert the answer to decimal

The given expression is raised to a power of 2, so we can say that the given expression is a quadratic equation.

What is a quadratic equation?

A quadratic equation is a form of an algebraic expression in which the variable is usually raised to the power of its second degree.

From the parameters given:

[tex]\mathbf{2(x + \dfrac{3}{4})^2 -5 = 123 }[/tex]

  • Addition of +5 to both sides

[tex]\mathbf{2(x + \dfrac{3}{4})^2 -5 +5 = 123+5 }[/tex]

[tex]\mathbf{2(x + \dfrac{3}{4})^2 = 128}[/tex]

  • Division of both sides by 2

[tex]\mathbf{\dfrac{2(x + \dfrac{3}{4})^2 }{2} =\dfrac{ 128}{2}}[/tex]

[tex]\mathbf{(x + \dfrac{3}{4})^2 = 64}[/tex]

  • Taking the square root of both sides

[tex]\mathbf{\sqrt{(x + \dfrac{3}{4})^2} =\sqrt{ 64}}[/tex]

[tex]\mathbf{(x + \dfrac{3}{4})} =\pm8}[/tex]

  • Subtract 3/4 from both sides

[tex]\mathbf{(x + \dfrac{3}{4} - \dfrac{3}{4}) }\mathbf{= \pm 8-\dfrac{3}{4}}[/tex]

[tex]\mathbf{x= \pm 8-\dfrac{3}{4}}[/tex]

[tex]\mathbf{x= +8-\dfrac{3}{4} \ \ OR \ \ x= -8-\dfrac{3}{4}} [/tex]

[tex]\mathbf{x=7.25 \ \ OR \ \ -8.75} [/tex]

Learn more about quadratic equations here:

https://brainly.com/question/17210919