cho 9g hỗn hợp al,mg,al2o3 vào dd naoh dư thu được 3,36l khí (đktc). nếu cho vào dd hcl dư thu được 7,84l khí (đktc) tính % khối lượng các chất trong hỗn hợp ban đầu

PART 3 Read the text. Choose the right words and write them on the lines. There is one example. We all_______________that trees are important. In (1)________________countries, there is even a day to celebrate trees. This day is called Arbor Day. However, do you know (2)_______________trees are so important? First of all, trees help (3)________________ our environment. The leaves on a tree take in air pollution. This makes our air cleaner. Trees also absorb. CO2 may contribute to global warming, the (4)________________in the Earth’s temperature. Thus, trees help prevent too (5)_______________CO2 from being in the air. Trees also naturally cool down the environment. (6)__________________ to scientific research, one young healthy tree is equivalent to ten room size air conditioners operating twenty hours a day. The leaves on a tree also create (7)________________, which cools the ground. This makes the air less hot. Also, (8)_____________ evaporates from tree leaves. This helps to cool the air further. All of these keep the surroundings cooler where trees (9)__________________. In addition, trees help (10)__________________ plants. The roots of trees support the soil (11)_____________them. If there is heavy rain or strong (12)_______________, the tree roots keep soil in place. This prevents erosion and (13)_________________ flooding. Finally, trees contribute to our personal (14)_________________. They cut down noise pollution. This decreases the stress on our bodies. As you can see, trees make many contributions to us and our (15)_______________. Have you hugged a tree lately? Example

(0) agree agreeting agreed

(1) much almost most

(2) what that why

(3) clean to mess improving

(4) decrease balance increase

(5) much many little

(6) Due According Owing

(7) shadow fan shade

(8) steam water liquid

(9) plant cut grow

(10) other the other another

(11) through across around

(12) wind cloud sun

(13) yet then even

(14) character happiness health

(15) family world area

Tính m(x) = a(x) -b(x)  biết a(x) = -3x^3 -2x^2 + 1 và x^3 +1 

tìm x và y biết :

a, x : y = 7/3 và 2x + 3y = 10 

b, x-y=5x+3y và  x+y=10

c, 3x+7y=10 và x-y=0

d, 2x+3y=5 x:y=2/3

cho đa thức: f(x) 3$x^2$-x +1 và g(x)= x-1

a). tính f(x). g(x)

b). tìm x để f(x). g(x)+$x^2$ [1-3.g(x)]= 5/2

giúp mik vs

Bài 3: Tìm x  N biết.

a)   (x + 4) chia hết (x + 1)

b)   3x chia hết (x – 1)

c)   (2x + 7) chia hết (x + 2)

Tính: 3 + 2^x-1 =(-2)^2 .3 + (-1)^2021

cho 33,3g hỗn hợp al và al2o3 tác dụng vùa đủ vs dd hcl 14,3% sau khi phản ứng xảy ra hoàn toàn thu được 10,08l khí (đktc). 

a)tính % khối lượng các chất trong hỗn họp ban đầu

tính c% dd sau phản ứng