4:

a: góc OAT+góc OMT=180 độ

=>OATM nội tiếp

b: Xét ΔAMC và ΔEOD có

góc MAC=góc OED

góc MCA=góc EDO

=>ΔAMC đồng dạng với ΔEOD

2 she had got the price of the contest, she would be happy now

3 I had gone to the concert last night ,I would be tired

4 John had finished all his homework, he could see a movie now

5 we had listened to my mother, we wouldn't be in trouble right now

Ex5

1 you arrive at the offcie earlier than I do, please turn on the air-conditioner

2 Were it not snowy, the children would go to school

3 he not died so young, he would be a famous musician

4 Were I you, I would take care of my car

5 not very bad-tempered, his wife would give him soon are marrage

6 Had she not got married at such an early age, he would be at university

Ta có:

x, y, z tỉ lệ với 3, 4, 5

=> x/3 = y/4 = z/5 = x - y/3 - 4 = 6/-1 = -6

Có: x/3 = -6 => x = -6.3 = -18

       y/4 = -6 => y = -6.4 = -24

       z/5 = -6 => z = -6.5 = -30

Ủng hộ nha

Ta có : \(\frac{x}{3}=\frac{y}{4}=\frac{z}{5}\Rightarrow\frac{x}{y}=\frac{3}{4}\)

Ta có hiệu số phần = nhau là :

 \(4-3=1\)phần

X là :

 \(6:1\times3=18\)

Y là :

 \(6:1\times4=24\)

Rồi bạn tự => ra z nha

12,12 x 7,5 + 12,12 : 2 + 12,12 + 12,12

= 12,12 x 7,5 + 12,12 x 0,5 + 12,12 x 1 + 12,12 x 1

= 12,12 x (7,5 + 0,5 + 1 + 1)

= 12,12 x 10

= 121,2

121,2 nha bạn

File: undefined 

giúp mình với

a: Ta có: \(A=\left(2x-1\right)^2+\left(2x-2\right)^3+\left(2x+3\right)^3\)

\(=8x^3-12x^2+6x-1+8x^3-16x^2+16x-8+\left(2x+3\right)^3\)

\(=16x^3-28x^2+22x-9+8x^3+36x^2+54x+27\)

\(=24x^3+8x^2+76x+18\)

\(A=8x^3-12x^2+6x-1+8x^3-24x^2+24x-8+8x^3+36x^2+54x+27\\ A=24x^3+84x^2+18\\ D=x^3-3x^2+3x-1+x^3-6x^2+12x-8-x^3+9x^2-27x+27\\ D=x^3-12x+18\)