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Find the mistake in the problem and explain why it is wrong

Find the mistake in the problem and explain why it is wrong-example-1

1 Answer

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\sf x^2 - 3x - 8 = 4


\longrightarrow \sf x^2 - 3x - 8 - 4 = 0


\longrightarrow \sf x^2 - 3x - {\red{12}} = 0

You had written (-4) instead of (-12)


\sf{\\}

Quadratic formula:-


\boxed{\sf{Roots = (-b \pm √(b^2 - 4ac))/(2a)}}


\sf{\\}

Here,

  • a = 1
  • b = -3
  • c = -12


\sf{\\}

By using quadratic formula,


\sf{ x_1 = (-(-3) + √((-3)^2 - 4(1)(-12)))/(2(1))}


\leadsto \underline{\boxed{\mathfrak{ \pink{x_1 = (3 + √(57))/(2)}}}}

Similarly,


\sf x_2 = (-(-3) - √((-3)^2 - 4(1)(-12)))/(2(1))


\leadsto \underline{\boxed{\mathfrak{\pink{ x_2 = (3 - √(57))/(2)}}}}

User Jonatasdp
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