Mathematics
Which of the following is a quadratic equation?
x2 - + 7 = 0
2x2 - 5x = (x - 1)2
x2 + = 2
Quadratic Equations
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Answer
Solving,
⇒ 2x2 - 5x = (x - 1)2
⇒ 2x2 - 5x = [(x)2 + (1)2 - 2 × x × 1]
⇒ 2x2 - 5x = x2 + 1 - 2x
⇒ 2x2 - 5x - x2 - 1 + 2x = 0
⇒ 2x2 - x2 - 5x + 2x - 1 = 0
⇒ x2 - 3x - 1 = 0
The highest power of equation is 2 and it's equivalent to ax2 + bx + c = 0 . Hence the equation is a quadratic equation.
Hence, option 2 is the correct option.
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