If x2 - 4x + 4 = 0, then the value of 16(x4 - 1/x4) is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e 255
| Understanding | Application |
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The roots of the quadratic equation ax2 + bx + c = 0 are [-b + √(b2 - 4ac)] / 2a & [-b - √(b2 - 4ac)] / 2a |
The roots of x2 - 4x + 4 = 0 ⇒ [4 - √(16 - 16] / 2 ⇒ 2 ⇒ 16(x4 - 1/x4) ⇒ 16(16 - 1 / 16) ⇒ 16(256 - 1) / 16 ⇒ 255 |