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Zacharias is using the quadratic formula to solve the equation 0 = –2x2 + 5x – 3. He begins by substituting as shown.

Quadratic formula: x = StartFraction negative b plus or minus StartRoot b squared minus 4 a c EndRoot Over 2 a EndFraction
Substitution: x = StartFraction negative 5 plus or minus StartRoot 5 squared minus 4(2)(negative 3) EndRoot Over 2(negative 2) EndFraction
What error did Zacharias make?

The –5 should be 5.
The 52 should be –52.
The 2 in the numerator should be –2.
The 2 in the denominator should be –2.

Respuesta :

Edufirst

Answer:

  • Third option: The 2 in the numerator should be –2.

Explanation:

These are the steps made by Zacharias:

  • Quadratic formula:

  • [tex]x=\frac{-b+/-\sqrt{b^2-4(a)(c)} }{2a}[/tex]

  • [tex]x=\frac{-5+/-\sqrt{5^2-4(2)(-3)} }{2(-2)}[/tex]

The equation to be solved using the quadratic formula is:

  • [tex]0=-2x^2+5x-3[/tex]

The parameters a, b, and c used in the quadratic formula correspond to the parameters in the general form:

  • [tex]ax^2+bx+c=0[/tex]

Thus, you have:

  • [tex]a=-2,b=5,c=-3[/tex]

And when you substitute you get:

  • [tex]x=\frac{-5+/-\sqrt{(-5)^2-4(-2)(-3)} }{2(-2)}[/tex]

  • [tex]x=\frac{-5+/-\sqrt{(5)^2-4(-2)(-3)} }{2(-2)}[/tex]

        (since the -5 in the radicand is raised to an even power, you can omit the negative sign).

Now you can see that the error that Zacharias made was that the 2 in the numerator (in the radicand) should be - 2.

Answer:the third option

Step-by-step explanation:

2,-2

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