`B=a(b^2-c^2)+b(c^2-a^2)+c(a^2-b^2)`
`B=ab(b-a)+c^2(b-a)-c(a+b)(b-a)`
`B=(b-a)(ab+c^2-ac-bc)`
`B=(b-a)[a(b-c)-c(b-c)]`
`B=(b-a)(b-c)(a-c)`
Đáp án:
`b)B=(b-a)(b-c)(a-c)`
Giải thích các bước giải:
`b)B=a(b^2-c^2)+b(c^2-a^2)+c(a^2-b^2)`
`=ab^2-ac^2+bc^2-a^2b+c(a+b)(a-b)`
`=(ab^2-a^2b)+(bc^2-ac^2)-c(a+b)(b-a)`
`=ab(b-a)+c^2(b-a)-c(a+b)(b-a)`
`=(b-a)[ab+c^2-c(a+b)]`
`=(b-a)(ab+c^2-ac-bc)`
`=(b-a)[(ab-ac)-(bc-c^2)]`
`=(b-a)[a(b-c)-c(b-c)]`
`=(b-a)(b-c)(a-c)`
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Hình thang ABCD (AD // BC) có tia phân giác của góc A và góc D gặp nhau tại điểm E thuộc BC. Chứng minh: a. BC=AB+CD b. Nếu góc AED=90 độ thì AB//CD
III. Gap fill: vulnerable, relieved, contented, blocked, kind-hearted, muscular, staring, split, requires, panic 1. The air-hostess asked us to fasten our seat-belts and not to _________. 2. The elderly are more____________to Corona virus. 3. He is tall, lean and ____________. 4. Social work ____________enthusiasm. 5. The cost of living is __________us in the face. 6. Such a ___________woman is worth our respect. 7. The house chores should be _________equally among family members. 8. The sofa can’t move because it is ____________. 9. It seems that few people are ___________with what they have. 10. I am __________to hear you are safe.
Cali tên ng mà bạn thích ( hoặc tên ai cx đc :D ) NL : ko có gì :)
prooooooooooooooooooooooooooooooo help me
EXERCISE 1: CHUYỂN CÁC CÂU SAU SANG BỊ ĐỘNG. 1. I had my nephew paint the gate last week. 2. She will have Peter wash her car tomorrow. 3. They have her tell the story again. 4. John gets his sister to clean his shirt. 5. Anne had had a friend type her composition. 6. Rick will have a barber cut his hair. 7. I will get the dressmaker to make a new dress. 8. He had a mechanic repair his car. 9. She often gets the technician to maintain the heater. 10. They had the police arrest the shoplifter. 11. Are you going to have the shoemaker repair your shoes? 12. I must have the dentist check my teeth. 13. She will have a veterinary surgeon examine her dog. 14. We had a man take this photograph when we were on holiday last summer. 15. The Greens had a carpet cleaner clean their carpet.
Giúp mình bài này vs ạ, thankiu
13.75+13.25-140 50 - [ 30-(6-2)^2}
Phân tích đa thức thành nhân tử
Cho tứ diện ABCD, M là trung điểm AD, G là trọng tâm tam giác BCD. Tìm I là giao của AG với (BMC).
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