HOC24
Lớp học
Môn học
Chủ đề / Chương
Bài học
22+6=28
28/2=14 nhé! SL=14
(x+3).(4-x)=7
⇒(x+3).(4-x)=7.1=1.7
TH1:Nếu x+3=7
⇒x=7-3=4 (1)
Nếu 4-x=1
x=4-1=3 (2)
Từ (1) và (2) suy ra xϵ∅
TH2:Nếu x+3=1
x=1-3=-2 (3)
Nếu 4-x=7
x=4-7=-3 (4)
Từ (3) và (4) suy ra xϵ∅
Từ trường hợp 1 và 2 suy ra xϵ∅
Vậy xϵ∅
Nhớ tck cho mình nha!!!!!!
VOLUNTEERS ABROAD
More and more young people are ... (28) ... voluntary work abroad. The wild variety of jobs and destinations available is making it an increasingly attractive option for those who have just left school and have a year free before university. Many choose to spend these twelve months working in poor countries. There they will earn little ... (29) ... no money. But they will be doing something useful – and enjoying the experience.
The work may ... (30) ... of helping the local communities, for example by helping to build new road or provide water supplies to isolated rural villages. Other projects may concentrate more on conservation or environmental protection. ... (31) ... kind of job it is, it is certain to be ... (32) ... and worthwhile, and an experience that will never be forgotten.
Question 31:
A. Any
B. What
C. However
D. Whatever
6a + 1 chia hết cho 2a - 1
6a - 3 + 4 chia hết cho 2a - 1
4 chia hết cho 2a - 1
2a - 1 thuộc U(4) = {-4;-2;-1;1;2;4}
2a - 1 lẻ => 2a- 1 = -1 hoặc 2a - 1 = 1
2a - 1 = -1 => a = 0
2a - 1 = 1 =>a = 1
c.cả hai đều đúng
(X + 7)(x - 9) = 0
TH1: x+ 7 = 0 => x= -7
TH2: x- 9 = 0 => x= 9
|x - 2| + |x + y| + |y +2z| = 0
=> |x - 2| = |x + y| = |y +2z| = 0
=> x= 0 + 2 = 2
=> |2 + y| = 0=> y = -2
=> |-2 + 2z| = 0 => 2z = 2 => z = 1
đây là tin học chứ ko phải GDCD nhé bn!!!!!!!!