ở chỗ 19?16 là em viết sai thật là 19/16 ạ

Mọi người trả lời nhanh giúp em với ạ

Giúp mik vs mik cung đang cân

\(P=\dfrac{x^2+x+1}{\left(x-1\right)^2}\)

Điều kiện: x≠ \(1\)

Ta có:

 \(P=\dfrac{\left(x^2-2x+1\right)+\left(3x-3\right)+3}{\left(x-1\right)^2}\)

 \(=\dfrac{\left(x-1\right)^2+3\left(x-1\right)+3}{\left(x-1\right)^2}\)

\(=1+\dfrac{3}{x-1}+\dfrac{3}{\left(x-1\right)^2}\)

\(=3\left[\left(\dfrac{1}{x-1}\right)^2+2.\dfrac{1}{x-1}.\dfrac{1}{2}+\dfrac{1}{4}\right]+\dfrac{1}{4}\)

\(=3\left(\dfrac{1}{x-1}+\dfrac{1}{2}\right)^2+\dfrac{1}{4}\) ≥ \(\dfrac{1}{4}\) (Vì \(3\left(\dfrac{1}{x-1}+\dfrac{1}{2}\right)^2\text{≥}0\) )

Min P=\(\dfrac{1}{4}\) ⇔\(x=-1\)

\(x^2-2x+y^2+4y+8=x^2-2x+1+y^2+4y+4+3=\left(x-1\right)^2+\left(y+2\right)^2+3\ge3\)

\(MinE=3\Leftrightarrow x=1;y=-2\)

Ta có: \(A=\left(x-3\right)^2+\left(11-x\right)^2\)

\(=x^2-6x+9+x^2-22x+121\)

\(=2x^2-28x+130\)

\(=2\left(x^2-14x+49+16\right)\)

\(=2\left(x-7\right)^2+32\ge32\forall x\)

Dấu '=' xảy ra khi x=7

help me 

Bn tham khảo

2A=1+1/2+1/4+1/8+1/16+1/32+1/64

2A-A=(1+1/2+1/4+1/8+1/16+1/32+1/64)-(1/2+1/4+1/8+1/16+1/32+1/64+1/128)

A=1-1/128

A=127/128

A = 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128

suy ra: 2A = 1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64

2A - A = 1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 - 1/2 - 1/4 - 1/8 - 1/16 - 1/32 - 1/64 - 1/128

A = 1 - 1/128 = 127/128

hok tốt

Dây nè nhớ nghe                                                                                                                                                                                =  1-1/2+1/2-1/4+1/4-1/8+1/8-1/16+1/16-1/32+1/32-1/64+1/64-1/128                                                                                                                   =1-1/128                                                                                                                                                                                                                  = 127/128

Bài 1 :

a, \(\frac{3}{4}:x=\frac{5}{12}\)

\(x=\frac{3}{4}:\frac{5}{12}\)

\(x=\frac{9}{5}\)

b, \(x-\frac{1}{2}=\frac{3}{4}:\frac{3}{2}\)

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

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

\(x=1\)

c, \(1\frac{1}{2}x-\frac{1}{2}=\frac{3}{4}\)

\(\frac{3}{2}x-\frac{1}{2}=\frac{3}{4}\)

\(\frac{3}{2}x=\frac{3}{4}+\frac{1}{2}\)

\(\frac{3}{2}x=\frac{5}{4}\)

\(x=\frac{5}{4}:\frac{3}{2}\)

\(x=\frac{5}{6}\)

Bài 2 :

\(A=\frac{-3}{5}+\left(\frac{-2}{5}-99\right)\)

\(A=\frac{-3}{5}+\frac{-2}{5}-99\)

\(A=\left(-1\right)-99\)

\(A=-100\)

\(B=\left(7\frac{2}{3}+2\frac{3}{5}\right)-6\frac{2}{3}\)

\(B=\left(\frac{23}{3}+\frac{13}{5}\right)-\frac{20}{3}\)

\(B=\frac{23}{3}+\frac{13}{5}-\frac{20}{3}\)

\(B=\left(\frac{23}{3}-\frac{20}{3}\right)+\frac{13}{5}\)

\(B=1+\frac{13}{5}\)

\(B=\frac{18}{5}\)

a, 3/4 : x = 5/12

=>        x = 3/4 : 5/12

=>        x = 9/5

Vậy x=9/5

b, x - 1/2 = 3/4 : 3/2

=>x - 1/2 = 1/2

=>x         = 1/2 + 1/2

=>x         = 2/2 = 1

Vậy x = 1

c, 11/2 . x - 1/2 = 3/4

=>11/2 . x         = 3/4 + 1/2

=> 11/2 . x        = 5/4

=>         x          = 5/4 : 11/2

=>          x         = 5/22

Vậy x = 5/22

Bài 2 :

A = -3/5 + ( -2/5 - 99 )

   = -3/5  +  -497/5

   =  -500/5

   =  -100

Vậy A = -100

B = ( 72/3 + 23/5 ) - 62/3

   =  429/15    - 62/3

   =       119/15

Vậy B = 119/15