???

a: AN+CN=AC

=>AN=20-15=5cm

Xét ΔABC có AM/AB=AN/AC

nên MN//BC

b: Xét ΔAMN và ΔNPC có

góc AMN=góc NPC(=góc B)

góc ANM=góc NCP)

=>ΔAMN đồng dạng với ΔNPC

a: ĐKXĐ: x<>0; x<>1(A)

(B): x<>0; x<>3

(C): x<>2; x<>-2

b: \(A=\dfrac{2\left(x-1\right)}{x\left(x-1\right)}=\dfrac{2}{x}\)

\(B=\dfrac{2\left(x-3\right)}{x\left(x-3\right)}=\dfrac{2}{x}\)

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

c: Khi x=0 thì A và B không xác định

Khi x=0 thì C=3/2

Khi x=3 thì B ko xác định, A=2/3; C=3/5

\(a,DKXD:\)

\(+x^2-x\ne0\Leftrightarrow x\ne0;1\)

\(+x^2-3x\ne0\Leftrightarrow x\ne0;3\)

+\(x^2-4\ne0\Leftrightarrow x\ne\pm4\)

\(b,\)

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

\(\dfrac{2x-6}{x^2-3x}=\dfrac{2\left(x-3\right)}{x\left(x-3\right)}=\dfrac{2}{x}\)

\(\dfrac{3x-6}{x^2-4}=\dfrac{3\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}=\dfrac{3}{x+2}\)

\(c,\)

Vì phân thức 1,2 cùng kết quả nên mk lm 1 cái thôi nhé

+ Thay \(x=0\) vào \(\dfrac{2}{x}\Leftrightarrow\dfrac{2}{0}=0\)

   Thay \(x=3\) vào \(\dfrac{2}{x}\Leftrightarrow\dfrac{2}{3}\) 

+ Thay \(x=0\) vào \(\dfrac{3}{x+2}\Leftrightarrow\dfrac{3}{0+2}=\dfrac{3}{2}\)

   Thay \(x=3\) vào \(\dfrac{3}{x+2}\Leftrightarrow\dfrac{3}{3+2}=\dfrac{3}{5}\)

86712 * 482947 =41881646787

chúc bạn học tốt

mik nhầm 41877300264 mới đúng

They build this house last year.

They (paint) paint yellow and they (like) like (live) living here. They (live) have lived here for 10 months._{(có đúng không nhỉ?:^)}

They built this house last year.
They painted it yellow and they liked living here. They have been living here for 10 months.

c)\(\left(1+\dfrac{1}{2}\right)\left(1+\dfrac{1}{3}\right)\left(1+\dfrac{1}{4}\right)....\left(1+\dfrac{1}{2020}\right)\left(1+\dfrac{1}{2021}\right)\)

\(=\left(\dfrac{1.2}{1.2}+\dfrac{1}{2}\right)\left(\dfrac{1.3}{1.3}+\dfrac{1}{3}\right)...\left(\dfrac{1.2021}{1.2021}+\dfrac{1}{2021}\right)\)

\(=\dfrac{3}{1.2}\cdot\dfrac{4}{1.3}\cdot\cdot\cdot\cdot\dfrac{2022}{1.2021}\)

\(=\dfrac{3.4.5...2022}{\left(1.1.1....1\right)\left(2.3.4...2021\right)}\)

\(=\)\(\dfrac{3.4.5...2022}{2.3.4...2021}\)

\(=\dfrac{2022}{2}=1011\)

\(d\))\(\left(1-\dfrac{1}{2}\right)\left(1-\dfrac{1}{3}\right)....\left(1-\dfrac{1}{199}\right)\left(1-\dfrac{1}{200}\right)\)

\(=\left(\dfrac{2}{1.2}-\dfrac{1}{1.2}\right)\left(\dfrac{3}{1.3}-\dfrac{1}{1.3}\right)....\left(\dfrac{200}{1.200}-\dfrac{1}{1.200}\right)\)

\(=\dfrac{1.2.3....199}{\left(1.1.1....1\right).\left(2.3.4....200\right)}\)

\(=\dfrac{1.2.3...199}{2.3.4...200}\)

Nếu mik làm sai mong bạn thông cảm

1/200

190 đường thẳng. học tốt nha bạn :)

190 đường thẳng