Để phân số n-4/n-6 là 1 số nguyên thì

2 câu trả lời

Đáp án+Giải thích các bước giải:

Để phân số n-4n-61 số nguyên thì n-4n-6

n-4n-6

(n-4)-(n-6)n-6

n-4-n+6n-6

2n-6

n-6Ư(2)={±1;±2}

Ta có bảng sau:

n-61212n7854

Vậy n{7;8;5;4} thì n-4n-61 số nguyên

Đáp án+Giải thích các bước giải:

Ta có: n-4n-6

=n-6+2n-6 

=n-6n-6+2n-6

=1+2n-6

Để n-4n-6 nguyên

2n-6 nguyên

n-6 là ước của 2

n-6{2;1;-1;-2}

[n6=2n6=1n6=1n6=2 

[n=8n=7n=5n=4 

Vậy x{8;7;5;4} thì n-4n-6 nguyên

Câu hỏi trong lớp Xem thêm

I. Reorder the words and write the meaning sentences. 1. city / beautiful / a / Ho Chi Minh / is. . ………………………………………….. 2. green fields / there / are. . …………………………………………………………. 3. dog / it’s / friendly / a. . ……………………………… 4. student / Minh / new / a/ is. . ……………………………………………………………… 5. television / big / a / there’s. . ………………………………………………………… 6. new / four / there / cars / are. . …………………………………………………… 7. are / two / pizzas / there / big. . ………………………………………………………………………….. 8. ten / are / desks / small / there. . ……………………………………………………………….. II. Use the given words to make complete sentences. 1. house/ a/ Minh/ lake/ a/ lives/ in/ near. ……………………………………………………………… 2. yard/ front/ school/There/ big/ of/ is/ our/ in/ a. ……………………………………………………………. 3. many/ right/ the/ museum/ Are/ flowers/ the/ there/ to/ of/? ………………………………………………………………….. 4. next/ photocopy/ What/ store/ there/ the/ is/ to /? ……………………………………………………………………… 5. hospital/ father/ in/ the/ city/ 2yiy/ a/ works/ in. ……………………………………………………………………. 6. there/ family/ many/ in/ are/ How/ Linh’s/ people/ ? …………………………………………………………………….. 7. his/ friend/ in/ family/ My/ Hanoi/ doesn’t/ with/ live. ……………………………………………………………………. 8. brushes/six/gets/her/o’clock/Hoa/at/up/teeth/and. ………………………………………………………………………… 9. on/ floor/ classroom/ the/ is/ Our/ first. ……………………………………………………………………………… 10. Minh’s/ six/ There/ in/ rooms/ house/ are. …………………………………………………………………… III. Rearrange the sentences. 1. house/ is/ the market/ far/ to/ from/ how/ it/ Trang’s? ……………………………………………………………………………………………. 2. lives/ street/ grandparents/ he/ Hoang Quoc Viet /his / on/ with. ……………………………………………………………. 3. many /old / students/ my/have/ doesn’t/ class. ………………………………………………………. 4. Mrs/ the boy/ to/ who/ Quyen/ talking/ is? ……………………………………………………………………………… 5. new / Hoa’s/ small/ school/ is. ……………………………………………………………………………….. 6. goes/ bus/ Hoang/ day/ work/ Mr./ every/ to/by. ………………………………………………………………………. 7. new/ from/ one/ is/ house/ his/ how/ different/ Minh’s/ old? …………………………………………………………………………. 8. because/ children/ is/ she/ Mrs.Diep /misses/ unhappy/ her. …………………………………………..

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