求正解,教教我阿數學根號式的運算?
回答 (1)
(1)
√(4x²) + √9y² + √(x - y)²
= √(2x)² + √(3y)² + √(x - y)²
= |2x| + |3y| + |x - y|
= (-2x) + (-3y) + [-(x - y)]
= -2x - 3y - x + y
= -3x - 2y
註:
因為 2x < 0,所以 |2x| = -2x
因為 3y < 0,所以 |3y| = -3y
因為 x - y < 0,所以 |x - y| = -(x - y)
(2)
∛(8x³) + ∛(27y³) + ∛(x - y)³
= ∛(2x)³ + ∛(3y)³ + ∛(x - y)³
= 2x + 3y + (x - y)
= 2x + 3y + x - y
= 3x + 2y
收錄日期: 2021-05-01 13:47:08
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