Question

which of the following are quadratic equations.
( DON'T DO DIRECTLY SOLVE PROPERLY PLEASE)

1. x square - 8 x + 12 is equal to zero
2. 4x2 + 7x - root5 = 0
3. 4root3x2 - 5/2x3 + 4 = 0
4. 2x - 15/x2 = 13
5. 17x2 - 20x + 10 = 10x + 2x +7

Answer 1

$1. \: {x}^{2} - 8x + 12 = 0 \\ \text{highest power of equation is 2.} \\ \text{So it is quadratic equation.}$
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$2. \: 4 {x}^{2} + 7x - \sqrt{5} = 0 \\ \text{highest power of equation is 2.} \\ \text{So it is a quadratic equation.}$
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$3. \: 4 \sqrt{3} \ {x}^{2} - \frac{5}{2} {x}^{3} + 4 = 0 \\ \text{highest power of equation is 3.} \\ \text{So it is not a quadratic equation.}$
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$4. \: 2x- \frac{15}{ {x}^{2} } = 13 \\ \\ 2 {x}^{3} - 15 = 13 {x}^{2} \\ \text{highest power of equation is 3.} \\ \text{So it is not a quadratic equation.}$
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$5. \: 17 {x}^{2} - 20x + 10 = 10x + 2x +7 \\ \\ 17 {x}^{2} - 32x + 3 = 0 \\ \\ \text{highest power of equation is 2.} \\ \text{So it is a quadratic equation.}$