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Use the quadratic formula, [tex][tex]$x=\frac{-b \pm \sqrt{b^2-4ac}}{2a}$[/tex][/tex], to solve the equation [tex][tex]$2x^2-8x+7=0$[/tex][/tex]. Round to the nearest hundredth.

A. [tex][tex]$x=-2.71$[/tex][/tex] and [tex][tex]$x=-1.29$[/tex][/tex]
B. [tex][tex]$x=1.29$[/tex][/tex] and [tex][tex]$x=2.71$[/tex][/tex]
C. [tex][tex]$x=-5.25$[/tex][/tex] and [tex][tex]$x=9.25$[/tex][/tex]
D. [tex][tex]$x=5.17$[/tex][/tex] and [tex][tex]$x=10.83$[/tex][/tex]


Sagot :

Let's solve the quadratic equation [tex]\(2x^2 - 8x + 7 = 0\)[/tex] using the quadratic formula:

The quadratic formula is given by:
[tex]\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \][/tex]

First, let's identify the coefficients [tex]\(a\)[/tex], [tex]\(b\)[/tex], and [tex]\(c\)[/tex] in the quadratic equation [tex]\(2x^2 - 8x + 7 = 0\)[/tex]:
- [tex]\(a = 2\)[/tex]
- [tex]\(b = -8\)[/tex]
- [tex]\(c = 7\)[/tex]

Next, we will calculate the discriminant, which is given by:
[tex]\[ \text{discriminant} = b^2 - 4ac \][/tex]

Substituting the values of [tex]\(a\)[/tex], [tex]\(b\)[/tex], and [tex]\(c\)[/tex], we get:
[tex]\[ \text{discriminant} = (-8)^2 - 4 \cdot 2 \cdot 7 = 64 - 56 = 8 \][/tex]

Now, we will calculate the two possible solutions using the quadratic formula:
[tex]\[ x_{1,2} = \frac{-b \pm \sqrt{\text{discriminant}}}{2a} \][/tex]

Substituting the values:
[tex]\[ x_{1,2} = \frac{-(-8) \pm \sqrt{8}}{2 \cdot 2} = \frac{8 \pm \sqrt{8}}{4} \][/tex]

We simplify the expression under the square root and further solve for [tex]\(x_1\)[/tex] and [tex]\(x_2\)[/tex]:

[tex]\[ x_1 = \frac{8 + \sqrt{8}}{4} \][/tex]
[tex]\[ x_2 = \frac{8 - \sqrt{8}}{4} \][/tex]

Finally, to get the values rounded to the nearest hundredths place, we proceed with the computation:

After calculating:
[tex]\[ x_1 \approx 2.71 \][/tex]
[tex]\[ x_2 \approx 1.29 \][/tex]

Thus, the solutions to the quadratic equation [tex]\(2x^2 - 8x + 7 = 0\)[/tex] rounded to the nearest hundredths place are:
[tex]\[ x = 1.29 \quad \text{and} \quad x = 2.71 \][/tex]

So, the correct answer is:
[tex]\[ x = 1.29 \quad \text{and} \quad x = 2.71 \][/tex]