tìm cận:x-1=0 ->x=1

x-4=0->x=

tìm cận:x 1 4

x-1 - 0 - +

x-4 - - 0 +

TH1:-(x-1)-(x-4)=3x

TH2:(x-1)-(x-4)=3x

TH3:(x-1)+(x-4)=3x

Bạn tự giải ra nha.câu b làm tương tự

Phương trình bậc hai z 2 + a z + b = 0 (a, b thuộc R) có một nghiệm là 3 -2i. Tính S = 2a -b.

A. S = 25

B. S = -32

C. S = -25

D. S = 32

<=> 7 + \(2^{x+1}\)=28-[16-3]

<=>7 + \(2^{x+1}\)=28-13

<=>7 + \(2^{x+1}\)=15

<=>\(2^{x+1}=8\)

<=>\(2^{x+1}=2^3\)

<=>x+1=3

<=>x=2

Giả sử alen trội là trội hoàn toàn. Phép lai nào sau đây cho đời con mỗi kiểu hình luôn có 2 kiểu gen khác nhau?

A. AA x Aa

B. Aa x Aa

C. AA x aa

D. Aa x aa

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.

        In the early 1800s, to reach the jump-off point for the West, a family from the East of the United States could either buy a steamboat passage to Missouri for themselves, their wagons and their livestock or, as happened more often, simply pile everything into a wagon, hitch up a team, and begin their overland trek right in their front yard.

        Along the macadamized roads and turnpikes east of the Missouri River, travel was comparatively fast, camping easy, and supplies plentiful. Then, in one river town or another, the neophyte emigrants would pause to lay in provisions. For outfitting purposes, the town of Independence had been preeminent ever since 1827, but the rising momentum of pioneer emigration had produced some rival jump-off points. Westport and Fort Leavenworth flourished a few miles upriver. St. Joseph had sprung up 55 miles to the northwest; in fact, emigrants who went to Missouri by riverboat could save four days on the trail by staying on the paddle wheelers to St. Joe before striking overland.

        At whatever jump-off point they chose, the emigrants studied guide books and directions, asked questions of others as green as themselves, and made their final decision about outfitting. They had various, sometimes conflicting, options. For example, either pack animals or two -wheel carts or wagons could be used for the overland crossing. A family man usually chose the wagon. It was the costliest and slowest of the three, but it provided space and shelter for children and for a wife who likely as not was pregnant. Everybody knew that a top-heavy covered wagon might blow over in a prairie wind or be overturned by mountain rocks, that it might mire in river mud or sink to its hubs in desert sand, but maybe if those things happened on this trip, they would happen to someone else. Anyway, most pioneers, with their farm background, were used to wagons.

All of the following features of the covered wagon made it unattractive to the emigrants EXCEPT _________.

A. its bulk

B. the speed at which it could travel

C. its familiarity and size 

D. its cost