化简 (sqrt(a)-7)^2

解答

化简

(a - 7)^{2}

a - 14 a + 49

求解步骤

(a - 7)^{2}

使用完全平方公式:

(a - b)^{2} = a^{2} - 2 ab + b^{2}

(a - 7)^{2} = (a)^{2} - 2 a \cdot 7 + 7^{2}

= (a)^{2} - 2 a \cdot 7 + 7^{2}

(a)^{2} = a

- 2 a \cdot 7 = - 14 a

7^{2} = 49

= a - 14 a + 49

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