giúp mk với mọi người ơi mk đang cần gấp. Chiều nay mk phải nộp rồi
Bài 3: giải phương trình:
\(\sqrt{2x+5}-\sqrt{3x-5}=2\)
giúp mk với mọi người ơi mk đang cần gấp. Tối nay mk phải nộp rồi.
Giải phương trình: \(\sqrt{2x^2+7x+10}+\sqrt{2x^2+x+4}=3x+3.\)
Mk muốn hỏi các bạn là phương trình này vô nghiệm có phải ko và nếu ko phải thì các bạn giải giúp mk nhé!
Giúp mk với, mk cần gấp trong ngày mai!
mọi người giúp mk với, mk đang cần gấp. Tối nay mk phải nộp rồi
B3: Cho biểu thức: C= \(\left(\dfrac{1}{\sqrt{a}-1}-\dfrac{1}{\sqrt{a}}\right)\left(\dfrac{\sqrt{a}+1}{\sqrt{a}-2}-\dfrac{\sqrt{a}+2}{\sqrt{a}-1}\right)\)
a. Hãy rút gọn C
b. Tìm a để C ≥ 1/6
Sửa đề: \(C=\left(\dfrac{1}{\sqrt{a}-1}-\dfrac{1}{\sqrt{a}}\right):\left(\dfrac{\sqrt{a}+1}{\sqrt{a}-2}-\dfrac{\sqrt{a}+2}{\sqrt{a}-1}\right)\)
\(a,C=\dfrac{\sqrt{a}-\sqrt{a}+1}{\sqrt{a}\left(\sqrt{a}-1\right)}:\dfrac{a-1-a+4}{\left(\sqrt{a}-1\right)\left(\sqrt{a}-2\right)}\left(a>0;a\ne1;a\ne4\right)\\ C=\dfrac{1}{\sqrt{a}\left(\sqrt{a}-1\right)}\cdot\dfrac{\left(\sqrt{a}-1\right)\left(\sqrt{a}-2\right)}{3}=\dfrac{\sqrt{a}-2}{3\sqrt{a}}\\ b,C\ge\dfrac{1}{6}\Leftrightarrow\dfrac{\sqrt{a}-2}{3\sqrt{a}}-\dfrac{1}{6}\ge0\Leftrightarrow\dfrac{\sqrt{a}-4}{6\sqrt{a}}\ge0\\ \Leftrightarrow\sqrt{a}-4\ge0\left(6\sqrt{a}>0\right)\\ \Leftrightarrow a\ge16\)
giúp mk với mọi người ơi mk đang cần gấp. Tối nay mk phải nộp rồi
hãy viết bài văn trình bày suy nghĩ của em về vai trò, ý nghĩa quan trọng của gia đình trong cuộc sống mỗi con người.
Giải PT:
\(\sqrt{x-1}\)+\(\sqrt{x+3}\)+\(2\sqrt{\left(x-1\right)\left(x^2-3x+5\right)}\)=4-2x
Các bạn ơi giải giúp mk với mai mk phải nộp cho cô rồi. Ai làm nhanh mk THƯỞNG 5 SAO
mọi người ơi giúp mk với mk đang cần gấp. Mai mk phải nộp rồi
giúp mk với mọi người ơi mk đang cần gấp. Chiều nay mk phải nộp rồi.
Exercise 2. Multiple choice questions.
1. ______ the Internet is very popular, many older people do not know how to use it
A. However B. Nevertheless C. Even though D. Despite
2. Ann: “Have you decided to get the job?” - Terry: “Yes, I‟ve just decided. I‟ll accept that job ______ it is not suitable with my major.
A. although B. despite C. so that D. because
3. Mary usually goes to parties. She likes meeting people and crowded places ______ she is rather shy.
A. In spite of B. Even though C. On the contrary D. In other words
4. I could not eat _______ I was very hungry.
A. even though B. since C. despite D. or else
5. ______ he had enough money, he refused to buy a new car.
A. In spite B. In spite of C. Despite D. Although
6. ______, he walked to the station.
A. Despite being tired B. Although to be tired C. In spite being tired D. Despite tired
7. The children slept well despite _______.
A. it was noise B. the noise C. of the noise D. noisy
8. ______, he could not finish the job.
A. As hard as he work B. Despite he worked hard C. Though he worked hard D. Although hard work
9. He went to work ______ his headache.
A. despite B. although C. because D. because of 10. Tom went to work despite _______.
A. that he did not feel very well B. of the fact not feeling well C. he did not feel very well D. not feeling very well
11. Despite _______, we arrived on time.
A. the traffic B. of the traffic C. there was heavy traffic D. of there was heavy traffic
12. ______ it was very cold, she did not put on her coat.
A. In case B. But C. Even if D. Although
13. ______ it was so cold, he went out without an overcoat.
A. If B. Since C. Although D. Because
14. We understood him ______ he spoke very fast.
A. because of B. though C. in spite of D. despite 15. ______ all my warnings, he tried to fix the computer himself.
A. Because B. Because of C. Although D. In spite of
16. ______ it rained heavily, we enjoyed our holiday.
A. Because of B. Because C. Despite D. Though 17. ______ having little money, they are happy. A. Despite B. Because of C. Although D. Because 18. ______ she was not well, she still went to work.
A. Because B. However C. Although D. In spite of
19. We are going to have a picnic ______ the bad weather.
A. so B. despite C. although D. because of
20. ______ his physical handicap, he has become a successful businessman.
A. Because of B. Since C. Though D. Despite 21. ______ his poor health, Mr. Brown still works hard to support his family. A. Even if B. Despite C. Although D. Because of
22. I gave up the job ______ the attractive salary. A. for B. because of C. although D. despite
23. ______ my father is old, he still goes jogging. A. Although B. Because C. So that D. Despite
24. The New Year‟s Eve is late at night. ______, children stay awake to welcome the New Year and to watch the firework display.
A. Therefore B. However C. Although D. Because
25. Sticky rice is very tasty, ______ it‟s hard to eat it every day.
A. and B. or C. so D. yet
26. ______ we were impressed by the new restaurant, we found it rather expensive.
A. Because B. Since C. Although D. Despite
27. Barbara is motivated to study ___ she knows that a good education can improve her life.
A. because B. because of C. due to D. owing to 28. He could not play in the game ___ his foot injury. A. because B. due to the fact that C. because of D. for
29. ___ I had nothing for lunch but an apple, I ate dinner early.
A. For B. Since C. Due to D. Because of
30. Mr. Watson retired from his job early ___ his ill health.
A. because B. due to C. as D. for
mọi người ơi giúp mk với mk đang cần gấp
tìm x : a, 9x^2-16-(3x-4)(2x+5)=0
b, x^2+4x=12
c, x^2-2x=35
Lời giải:
a. $9x^2-16-(3x-4)(2x+5)=0$
$\Leftrightarrow [(3x)^2-4^2]-(3x-4)(2x+5)=0$
$\Leftrightarrow (3x-4)(3x+4)-(3x-4)(2x+5)=0$
$\Leftrightarrow (3x-4)(3x+4-2x-5)=0$
$\Leftrightarrow (3x-4)(x-1)=0$
$\Leftrightarrow 3x-4=0$ hoặc $x-1=0$
$\Leftrightarrow x=\frac{4}{3}$ hoặc $x=1$.
b.
$x^2+4x=12$
$\Leftrightarrow x^2+4x-12=0$
$\Leftrightarrow (x^2-2x)+(6x-12)=0$
$\Leftrightarrow x(x-2)+6(x-2)=0$
$\Leftrightarrow (x-2)(x+6)=0$
$\Leftrightarrow x-2=0$ hoặc $x+6=0$
$\Leftrightarrow x=2$ hoặc $x=-6$
c.
$x^2-2x=35$
$\Leftrightarrow x^2-2x-35=0$
$\Leftrightarrow (x^2+5x)-(7x+35)=0$
$\Leftrightarrow x(x+5)-7(x+5)=0$
$\Leftrightarrow (x+5)(x-7)=0$
$\Leftrightarrow x+5=0$ hoặc $x-7=0$
$\Leftrightarrow x=-5$ hoặc $x=7$
Mọi người ơi giúp mk vs ạ mk đag cần gấp!
câu 1 Tìm x biết
a)\(\sqrt{2\text{x}-1}=\sqrt{5}\)
b)\(\sqrt{x-10}=-2\)
c)\(\sqrt{\left(x-5\right)}=3\)
a) \(\sqrt{2x-1}=\sqrt{5}\) (ĐK: \(x\ge\dfrac{1}{2}\))
\(\Leftrightarrow2x-1=5\)
\(\Leftrightarrow2x=6\)
\(\Leftrightarrow x=3\left(tm\right)\)
b) \(\sqrt{x-10}=-2\)
⇒ Giá trị của biểu thức trong căn luôn dương nên phương trình vô nghiệm
c) \(\sqrt{\left(x-5\right)^2}=3\)
\(\Leftrightarrow\left|x-5\right|=3\)
TH1: \(\left|x-5\right|=x-5\) với \(x-5\ge0\Leftrightarrow x\ge5\)
Pt trở thành:
\(x-5=3\) (ĐK: \(x\ge5\))
\(\Leftrightarrow x=3+5\)
\(\Leftrightarrow x=8\left(tm\right)\)
TH2: \(\left|x-5\right|=-\left(x-5\right)\) với \(x-5< 0\Leftrightarrow x< 0\)
Pt trở thành:
\(-\left(x-5\right)=3\) (ĐK: \(x< 5\))
\(\Leftrightarrow-x+5=3\)
\(\Leftrightarrow-x=-2\)
\(\Leftrightarrow x=2\left(tm\right)\)
Vậy: \(S=\left\{2;8\right\}\)
a/ ĐKXĐ: 2x - 1 >= 0 <=> 2x > 1 <=> x>= 1/2
\(\sqrt{2x-1}=\sqrt{5}\Leftrightarrow2x-1=5\Leftrightarrow2x=6\Leftrightarrow x=3\left(tm\right)\)
b/ ĐKXĐ: x - 10 >= 0 <=> x >= 10
Biểu thức trong căn luôn nhận giá trị dương => vô nghiệm
c/ ĐKXĐ: x - 5 >=0 <=> x >= 5
\(\sqrt{x-5}=3\Leftrightarrow x-5=9\Leftrightarrow x=14\left(tm\right)\)