1 .根号8减根号2小括号根号2加2 2.5倍根号2加根号8减7倍根号18

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1 .根号8减根号2小括号根号2加2 2.5倍根号2加根号8减7倍根号18

1 .根号8减根号2小括号根号2加2 2.5倍根号2加根号8减7倍根号18
1 .根号8减根号2小括号根号2加2 2.5倍根号2加根号8减7倍根号18

1 .根号8减根号2小括号根号2加2 2.5倍根号2加根号8减7倍根号18
√8-√2(√2+2)
=2√2-2-2√2
=-2
5√2+√8-7√18
=5√2+2√2-21√2
=-14√2

√8 - √2(√2 + 2)
= √(2 × 4)- √2 × √2 - 2√2
= √(2 × 2 ²)- 2 - 2√2
= 2√2 - 2 - 2√2
= (2 - 2)√2 - 2
= - 2

5√2 + √8 - 7√18
= 5√2 + √(2 × 4)- 7√(2 × 9)
= 5√2 + ...

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√8 - √2(√2 + 2)
= √(2 × 4)- √2 × √2 - 2√2
= √(2 × 2 ²)- 2 - 2√2
= 2√2 - 2 - 2√2
= (2 - 2)√2 - 2
= - 2

5√2 + √8 - 7√18
= 5√2 + √(2 × 4)- 7√(2 × 9)
= 5√2 + √(2 × 2 ²)- 7√(2 × 3 ²)
= 5√2 + 2√2 - 7 × 3√2
= (5 + 2)√2 - 21√2
= (7 - 21)√2
= - 14√2

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