ace ơi giúp mk với. Chiều mk cần nộp gấp:Tìm x:
12-| x+1/2 | = 3x -1
Giúp mk bài này với ạ, mk đg cần gấp:
Tìm x:
(x + 4)(x+2) - x2 =7
\(\Leftrightarrow x^2+6x+8-x^2=7\\ \Leftrightarrow6x=-1\Leftrightarrow x=-\dfrac{1}{6}\)
(x + 4)(x+2) - x2 =7
x2+ 2x + 4x + 8 - x2 = 7
6x + 8 = 7
6x = 7 - 8 = -1
=> x = \(\dfrac{-1}{6}\)
giúp mk với mọi người ơi mk đang cần gấp. Chiều nay mk phải nộp rồi
Bài 3: giải phương trình:
\(\sqrt{2x+5}-\sqrt{3x-5}=2\)
ĐK: \(x\ge\dfrac{5}{3}\)
Ta có: \(\sqrt{2x+5}=2+\sqrt{3x-5}\)
\(\Leftrightarrow2x+5=4+3x-5+4\sqrt{3x-5}\)
\(\Leftrightarrow6-x=4\sqrt{3x-5}\) ĐK: x≤6
\(\Leftrightarrow36-12x+x^2=48x-80\)
\(\Leftrightarrow x^2-60x+116=0\)
\(\Leftrightarrow\left(x-2\right)\left(x-58\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=58\end{matrix}\right.\)
So với điều kiện thì phương trình có nghiệm duy nhất là x = 2
\(ĐK:x\ge\dfrac{5}{3}\\ PT\Leftrightarrow\left(\sqrt{2x+5}-3\right)-\left(\sqrt{3x-5}-1\right)=0\\ \Leftrightarrow\dfrac{2x-4}{\sqrt{2x+5}+3}-\dfrac{3x-6}{\sqrt{3x-5}+1}=0\\ \Leftrightarrow\left(x-2\right)\left(\dfrac{2}{\sqrt{2x+5}+3}-\dfrac{3}{\sqrt{3x-5}+1}\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=2\left(tm\right)\\\dfrac{2}{\sqrt{2x+5}+3}=\dfrac{3}{\sqrt{3x-5}+1}\left(1\right)\end{matrix}\right.\)
\(\left(1\right)\Leftrightarrow2\sqrt{3x-5}+2=3\sqrt{2x+5}+9\\ \Leftrightarrow2\sqrt{3x-5}=7+3\sqrt{2x+5}\\ \Leftrightarrow4\left(3x-5\right)=49+9\left(2x+5\right)+42\sqrt{2x+5}\\ \Leftrightarrow12x-20=49+18x+45+42\sqrt{2x+5}\\ \Leftrightarrow-6x-144=42\sqrt{2x+5}\)
Vì \(x\ge\dfrac{5}{3}>0\Leftrightarrow-6x-144< 0< 42\sqrt{2x+5}\)
Do đó (1) vô nghiệm
Vậy PT có nghiệm \(x=2\)
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
Tim x biết:
a) 0,5x - 2/3x = 7/12
b) x : hỗn số 4 1/3 = -2,5
c)5,5x = 13/ 15
d) (3x /7 + 1) : (-4) = -1/ 28
(GIÚP MK BÀI NÀY VỚI CÁC CẬU MAI MK PHẢI NỘP BÀI RỒI BN NÀO CÓ LỜI GIẢI CHI TIẾT MK SẼ TICK)
mn ơi tính hộ mk bài tìm x với mk đang cần gấp::2 x 3X + 1=10 x 312 + 8 x 312
\(2.3^{x+1}=10.3^{12}+8.3^{12}\\ \Rightarrow2.3^{x+1}=3^{12}\left(10+8\right)\\ \Rightarrow2.3^{x+1}=3^{12}.18\\ \Rightarrow3^{x+1}=9.3^{12}\\ \Rightarrow3^{x+1}=3^{14}\\ \Rightarrow x+1=14\\ \Rightarrow x=13\)
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
12.x+3.2^3=2^3.x - 4.3^2
GIÚP MK VS MK ĐANG CẦN GẤP LỚP MK AI CX CẦN BÀI NÀY NẾU AI LÀM ĐÚNG MK BÁO CẢ LỚP TK CHO NHA! 1 TIẾNG NX NỘP R NHANH NHA!
12x+3.23=23.x-4.32
12x+3.8=8.x-4.9
12x+24=8x-36
12x-8x=36-24
4x=12
x=12:4=3
\(12x+3\cdot2^3=2^3x-4\cdot3^2\)
\(\Rightarrow12x+24=8x-36\)
\(\Rightarrow12x-8x=-36-24\)
\(\Rightarrow4x=-60\)
\(\Rightarrow x=-15\)
Vay x=-15
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 $x=7$