Where does the parabola $x^{2} - 3 x = 40$ $x^2-3x=40$ have roots?

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Where does the parabola $x^{2} - 3 x = 40$ $x^2-3x=40$ have roots?

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Answer 1 · 2017-05-11T12:42:33

$x = - 5 and x = 8$ $x=-5" and " x=8$

Explanation:

$rearrange and equate to zero$ $"rearrange and equate to zero"$

$\Rightarrow x^{2} - 3 x - 40 = 0$ $rArrx^2-3x-40=0$

$splitting the middle term gives$ $"splitting the middle term gives"$

$x^{2} - 8 x + 5 x - 40 = 0$ $x^2-8x+5x-40=0$

$factorising$ $"factorising"$

$x (x - 8) + 5 (x - 8) = 0$ $x(x-8)+5(x-8)=0$

$taking out the factor (x - 8)$ $"taking out the factor " (x-8)$

$\Rightarrow (x - 8) (x + 5) = 0 \leftarrow equate each factor to zero$ $rArr(x-8)(x+5)=0larr" equate each factor to zero"$

$x - 8 = 0 \Rightarrow x = 8$ $x-8=0rArrx=8$

$x + 5 = 0 \Rightarrow x = - 5$ $x+5=0rArrx=-5$

$\Rightarrow x = - 5 and x = 8 are the roots$ $rArrx=-5" and " x=8" are the roots"$
graph{x^2-3x-40 [-10, 10, -5, 5]}

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Where does the parabola $x^{2} - 3 x = 40$ $x^2-3x=40$ have roots?

1 Answer

Explanation:

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Science

Math

Humanities

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Where does the parabola x2−3x=40x^2-3x=40 have roots?

1 Answer

Explanation:

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Where does the parabola $x^{2} - 3 x = 40$ $x^2-3x=40$ have roots?