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17 tháng 7 2018

TH1: x ≥ 10 thì phương trình trở thành:

x - 10 - 2(x+1) =0

⇔ x -10 - 2x - 2 = 0

⇔ -x - 12 = 0

⇔ x = -12 (không thỏa mãn)

TH2: -1≤ x < 10 thì ptrình trở thành:

10 - x - 2(x +1) =0

⇔ 10 - x - 2x - 2=0

⇔8 - 3x =0

⇔ x = 8/3 (thỏa mãn)

TH3: x < -1 thì ptrình trở thành:

10 - x - 2(-x-1) =0

⇔ 10 - x +2x +2 =0

⇔12 + x =0

⇔ x = -12 (thỏa mãn)

Vậy ......... ( tự kết luận nha)

Bạn là Wannable ak???

17 tháng 7 2018

yes! And you?

26 tháng 3 2020

1. \(f\left(x\right)=x+x^2-6x^3+3x^4+2x^2+6x-2x^4+1\)

\(\Rightarrow f\left(x\right)=7x+3x^2-6x^3+x^4+1\)

Sắp xếp theo lũy thừa giảm dần của biến x:

\(f\left(x\right)=x^4-6x^3+3x^2+7x+1\)

2. Bậc của đa thức: 4

Hệ số tự do: 1

Hệ số cao nhất: 7

3. \(f\left(-1\right)=\left(-1\right)^4-6.\left(-1\right)^3+3.\left(-1\right)^2+7.\left(-1\right)+1=4\)

\(f\left(0\right)=0^4-6.0^3+3.0^2+7.0+1=1\)

\(f\left(1\right)=1^4-6.1^3+3.1^2+7.1+1=6\)

\(f\left(-a\right)=\left(-a\right)^4-6.\left(-a\right)^3+3.\left(-a\right)^2+7.\left(-a\right)+1=3a+1\)

\(\)

31 tháng 5 2019

Bạn có thể vào CHTT tham khảo

Hok tốt

NHTP

31 tháng 10 2017

1,

a) 3,2x +(-12)x +2,7=-4,9 b)-5,6x+2,9x-3,86=-9,8

=>3,2x+(-12)x=-4,9-2,7 =>-5,6x+2,9x=-9,8+3,86

=>3,2x+(-12)x=-7,6 =>-5,6x+2,9x=-5,94

=>x[3,2+(-12)]=-7,6 =>x[(-5,6)+2,9]=-5,94

=>2x=-7,6=>x=-7,6:2=-3,8 =>-2,7x=-5,94=>x=(-5,94):(-2,7)=2,2

31 tháng 10 2017

Nhầm môn r bạn ơi

19 tháng 7 2016

\(\left(-7\right)^x.\left(-7\right)^2=1\)

\(\Rightarrow\left(-7\right)^{x+2}=1\)

\(\Rightarrow\left(-7\right)^{x+2}=\left(-7\right)^0\)

=>x+2=0

=>x=-2

19 tháng 7 2016

\(\left(-7\right)^x=\frac{1}{49}\)

\(\left(-7\right)^x=\left(-7\right)^{-2}\)

\(x=-2\)

18 tháng 5 2021

ai giúp mik với


 

18 tháng 5 2021

\(4x-3-x-5=30-3x\Leftrightarrow4x-x+3x=30+3+5\Leftrightarrow6x=38\Leftrightarrow x=\dfrac{19}{3}\)

31 tháng 10 2019

 \(\frac{3}{7}-\frac{4}{7}:\left(x-1\right)=\frac{-5}{7}\)

\(\frac{4}{7}:\left(x-1\right)=\frac{3}{7}-\left(\frac{-5}{7}\right)=\frac{8}{7}\)

\(x-1=\frac{4}{7}:\frac{8}{7}\)

\(x-1=\frac{1}{2}\)

=> \(x=\frac{1}{2}+1=\frac{3}{2}\)

Vậy x= \(\frac{3}{2}\)
Chúc bạn học tốt !

31 tháng 10 2019

\(\frac{3}{7}-\frac{4}{7}:\left(x-1\right)=-\frac{5}{7}\)

\(\Leftrightarrow\frac{4}{7}:\left(x-1\right)=\frac{3}{7}-\left(-\frac{5}{7}\right)\)

\(\Leftrightarrow\frac{4}{7}:\left(x-1\right)=\frac{8}{7}\)

\(\Leftrightarrow x-1=\frac{4}{7}:\frac{8}{7}\)

\(\Leftrightarrow x-1=\frac{1}{2}\)

\(\Leftrightarrow x=1\frac{1}{2}\)

Vậy: \(x=1\frac{1}{2}\)

XII. Change the sentences into past simple tense.1. We have learned English for 10 years.=> ____________________________________________________________________.2. It has been a long time since we last met.=> ____________________________________________________________________.3. Ms. Ann hasn’t taken part in any voluntary programs for 4 years.=> ____________________________________________________________________.4. I haven’t mer my family since last Christmas.=>...
Đọc tiếp

XII. Change the sentences into past simple tense.

1. We have learned English for 10 years.

=> ____________________________________________________________________.

2. It has been a long time since we last met.

=> ____________________________________________________________________.

3. Ms. Ann hasn’t taken part in any voluntary programs for 4 years.

=> ____________________________________________________________________.

4. I haven’t mer my family since last Christmas.

=> ____________________________________________________________________.

5. How long have you lived here?

=> ____________________________________________________________________.

6. The volunteers have provided free food and fresh water to homeless people since yesterday.

=> ____________________________________________________________________.

7. The doctor has quitted his job in the local hospital and moved to the central hospital for 2 days.

=> ____________________________________________________________________.

8. The children haven’t had a long vacation since last year.

=> ____________________________________________________________________.

9. They haven’t visited their parents for 3 months.

=> ____________________________________________________________________.

10. It has been 2 years since we broke up.

=> _________________________________________________________________

2
18 tháng 9 2021

gì nhiều dữ vậy

18 tháng 9 2021

1. We started learning English 10 years ago. 

2. The last time we met was a long time ago.

3. The last time Mr.s Ann took part in many voluntary programs was 4 years ago.

4. The last time I met my family was (the) last Christmas.

5.  When did you start living here ?

6. The volunteers provided free food and fresh water to homeless people yesterday. 

7. The doctor quitted his job in the local hospital and moved to the central hospital 2 days ago. 

8. The last time the children had a long vacation was last year. 

9. The last time they visited their parents was 3 months ago.

10. We broke up 2 years ago. 

6 tháng 11 2021

Câu D Nha :   

We have asked people to donate books and clothes for the poor children so far.