Let's review Joana's steps to determine if her conclusion about the quadratic equation \( 4x^2 - 4x - 3 = 0 \) having no solutions is correct.
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Starting equation: \[ 4x^2 - 4x - 3 = 0 \]
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Step 1: Joana rewrote the equation as: \[ 4x^2 + 2x - 6x - 3 = 0 \] This step is correct as it still represents the same equation (the middle term \(-4x\) can be split into \(2x - 6x\)).
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Step 2: Joana grouped the terms: \[ (4x^2 + 2x) + (-6x - 3) = 0 \] This is also a correct grouping.
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Step 3: Joana factored each group: \[ x(4x + 2) - 3(2x + 1) = 0 \] This step contains an error. The factored forms are not presenting a common binomial correctly because \(4x + 2\) does not match with \(-3(2x + 1)\).
Resolving the equation using the quadratic formula:
The correct way to solve the quadratic equation is to apply the quadratic formula: \[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] For our equation, where \(a = 4\), \(b = -4\), and \(c = -3\):
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Calculate the discriminant: \[ b^2 - 4ac = (-4)^2 - 4(4)(-3) = 16 + 48 = 64 \] Since the discriminant is positive (\(64\)), this means that there are two real solutions.
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Finally, applying the quadratic formula: \[ x = \frac{-(-4) \pm \sqrt{64}}{2(4)} = \frac{4 \pm 8}{8} \] This gives us two solutions:
- \(x = \frac{12}{8} = \frac{3}{2}\)
- \(x = \frac{-4}{8} = -\frac{1}{2}\)
Conclusion:
Joana's conclusion that the quadratic equation has no solutions is not correct. The equation \(4x^2 - 4x - 3 = 0\) does have two real solutions.