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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: √a +a√b- √b- b√a/ab-1 nhanh hộ mình nha

Toán Lớp 8: √a +a√b- √b- b√a/ab-1
nhanh hộ mình nha

Comments ( 2 )

  1. Giải đáp:
    (√a+a√b- √b-b√a)/(ab-1)
    =(√a . (1 + √ab) – √b . ( 1+ √ab))/((√ab – 1).(√ab +1))
    = ( √a – √b )/(√ab -1 )

  2. ***Lời giải***
    \frac{\sqrt{a}+a\sqrt{b}-\sqrt{b}-b\sqrt{a}}{ab-1}
    =\frac{(\sqrt{a}-\sqrt{b})+(a\sqrt{b}-b\sqrt{a})}{ab-1}
    =\frac{(\sqrt{a}-\sqrt{b})+\sqrt{a}\sqrt{b}(\sqrt{a}-\sqrt{b})}{ab-1}
    =\frac{(\sqrt{a}-\sqrt{b})(1+\sqrt{a}\sqrt{b})}{(\sqrt{a}\sqrt{b})^2-1}
    =\frac{(\sqrt{a}-\sqrt{b})(1+\sqrt{a}\sqrt{b})}{(\sqrt{a}\sqrt{b}-1)(\sqrt{a}\sqrt{b}+1)}
    =\frac{\sqrt{a}-\sqrt{b}}{\sqrt{a}\sqrt{b}-1}

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222-9+11+12:2*14+14 = ? ( )