Bài 1:
`a)6x-18y`
`=6.x-6.3y`
`=6(x-3y)`
`b)2x³-6xy+4xy²`
`=2x.x²-2x.3y+2x.2y²`
`=2x(x²-3y+2y²)`
`c)3xyz²+6xy²z-9xyz`
`=3xyz.z+3xyz.2y-3xyz.3`
`=3xyz(z+2y-3)`
Bài 2:
`a)5x.(3x+y)-7y.(y+3x)`
`=5x.(3x+y)-7y.(3x+y)`
`=(3x+y)(5x-7y)`
`b)4x.(y-x)-y.(x-y)`
`=4x.(y-x)+y(y-x)`
`=(y-x)(4x+y)`
`c)2x.(3y-2)-15y+10`
`=2x.(3y-2)-(15y-10)`
`=2x.(3y-2)-5.(3y-2)`
`=(3y-2)(2x-5)`
`d)(3x+1).(2y-3)-(3-2y)²`
`=(3x+1).(2y-3)-(2y-3)²`
`=(2y-3)[(3x+1)-(2y-3)]`
`=(2y-3)(3x+1-2y+3)`
`=(2y-3)(3x-2y+4)`
Đáp án:
Giải thích các bước giải:
a) 6x - 18y
=6(x-3y)
b) 2x³-6xy+4xy²
=2x(x²-3y+2y²)
c) 3xyz²+6xy²z-9xyz
= 3xyz( z+2y-3)
a) 5x(3x+y)-7y(y+3x)
= (3x+y)(5x-7y)
b) 4x (y-x)-y(x-y)
= 4x (y-x)+y(y-x)
=(y-x)(4x-y)
c) 2x(3y-2)-15y+10
=2x(3x-2)-5(3y-2)
=(3x-2)(2x-5)
d) (3x+1)(2y-3)-(3-2y)²
= (3x+1)(2y-3)+(2y-3)²
=(2y-3)(3x+1+1)
=(2y-3)(3x+2)
Giải giúp em với ạ em cảm ơn trc ạ
1. They / wait / manager / since / 8 o’clock. 2. He / look after / younger brother / since / father / die. 3. She / have / Italian penfriend / since / she / 12 years old. 4. We / not / see / him / since / he / win / gold medal. 5. he / ever / take part / online auction? 6. How long / Mai / learn / English? 7. It / not / rain / this part / desert / 1936. 8. I / awake / 5 o’clock / this morning.
Lan bắt đầu đi từ nhà lúc 7h35 phút . lan đến trường lúc 8h kém 5 phút .thời gian lan đi từ nhà tới trường là
Helppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppp
1. This is the first time I have been to Japan. I have ….................................................................................. 2. This is the third time we have had Chinese food. We have ....................................................................... 3. I’ve never tasted pheasant before. This is ……………………………………………………………....... 4. We started cooking for the party 4 hours ago. We …………………………………………………......... 5. It started snowing half an hour ago. It ....................................................................................................... 6. They began to play football 3 hours ago. They ......................................................................................... 7. He last watched a movie 2 weeks ago. He hasn’t ….................................................................................. 8. They last visited to the zoo 3 months ago. They haven’t ….......................................................................... 9. It’s the most interesting film we’ve ever seen. We have ........................................................................... 10. It’s the most fantastic music I’ve ever heard. I have .................................................................................
cho phương trình $x^{2}$ + mx + 1 = 0 (m là tham số khác 0 ) Tìm m để phương trình có 2 nghiệm $x_{1}$, $x_{2}$ thỏa mãn điều kiện:
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