Đáp án+Giải thích các bước giải:
a, 2$\sqrt{3}$ - $\sqrt{4 + x²}$ = 0
⇔ $\sqrt{4 + x²}$ = 2$\sqrt{3}$
⇒ 4 + x² = 12
⇔ x² = 8
⇔ x = ± 2$\sqrt{2}$
b, 3$\sqrt{2x}$ + 5$\sqrt{8x}$ - 20 - $\sqrt{18x}$ = 0 (ĐKXĐ : x ≥ 0 )
⇔ 3$\sqrt{2x}$ + 5$\sqrt{4.2x}$ - 20 - $\sqrt{9.2x}$ = 0
⇔ 3$\sqrt{2x}$ + 10$\sqrt{2x}$ - 20 - 3$\sqrt{2x}$ = 0
⇔ 10$\sqrt{2x}$ = 20
⇔ $\sqrt{2x}$ = 2
⇒ 2x = 4
⇔ x = 2 (tmđk)
`a)2sqrt3-sqrt{4+x^2}=0`
`<=>2sqrt3=sqrt{x^2+4}`
`<=>x^2+4=(2sqrt3)^2=12`
`<=>x^2=8`
`<=>x=+-2sqrt2`
`=>S={2sqrt2,-2sqrt2}.`
`b)3sqrt{2x}+5sqrt{8x}-20-sqrt{18x}=0(x>=0)`
`<=>3sqrt{2x}+10sqrt{2x}-20-3sqrt{2x}=0`
`<=>10sqrt{2x}=20`
`<=>sqrt{2x}=2`
`<=>2x=4`
`<=>x=2(tm)`
`=>S={2}.`
Find and correct the mistake 1.He surprised by the loud noise. 2. They were ate dinner at six o'clock. 3. Was your car fix? 4. This photo was take by my uncle. 5. Who was cooked dinner? 6. When did the airplane invented? 7. He was watched his favorite TV show. 8. Robert was bite by a dog. 9. They were interview by a reporter. 10.I'm sorry. You are not allow to go inside. 11. Pluto discovered in 1930. 12. Why did the party cancelled? 13. I was really enjoyed my holiday last summer. 14. My friend wasn't careful. She was fell off her bicycle. 15. The room cleaned this morning 16. When was the story write
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Đốt cháy hoàn toàn 2,76 gam hỗn hợp X gồm CxHyCOOH, CxHyCOOCH3, CH3OH thu được 2,688 lít CO2 (đktc) và 1,8 gam H2O. Mặt khác, cho 2,76 gam X phản ứng vừa đủ với 30 ml dung dịch NaOH 1M, thu được 0,96 gam CH3OH. Công thức của CxHyCOOH là A. C2H5COOH B.CH3COOH C. C2H3COOH D. C3H5COOH
My grandmother had always wanted to watch Khanh Ly (PERFORMANCE) _______ live once, but she could never afford to.
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@ voquistruong giải giúp mk phần b
`NN\{0}` là kí hiệu gì? Đọc lên
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LÀM NHANH ĐC K Ạ TẦM 5H XONG LÀ ĐC
Give the correct form of the word given to complete the sentences
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