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Suppose that 2x^2 - 5x + k = -x^2 + 3x is a quadratic equation with one solution for x. Express k as a common fraction.

 Jul 6, 2022
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Simplify to \(3x^2 - 8x + k = 0\)

 

If the quadratic has exactly 1 solution, then it can be expressed as \(a(x-h)^2 \), where h is the x-coordinate of the vertex. 

 

We know that \(a = 3\), because it is the leading coefficient of the \(x^2\) term.

 

Also, note that \(2h \times 3 = 8\), meaning \(h = {4 \over 3}\).

 

This means we have \(3(x-{4 \over 3})^2\), which expands to \(3x^2 - 8x + {16 \over 3}\), meaning \(k = \color{brown}\boxed{16 \over 3}\)

 Jul 6, 2022

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