các bn làm giúp mình nhé mình đang cần gấp
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NM
0
7 tháng 10 2021
b) Ta có :
-3x + 2y = 55
\(\frac{x}{4}=\frac{y}{-5}=\frac{-3x}{-12}=\frac{2y}{-10}\)
Áp dụng tính chất dãy tỉ số bằng nhau , ta có :
\(\frac{x}{4}=\frac{y}{-5}=\frac{-3x}{-12}=\frac{2y}{-10}=\frac{-3x+2y}{-12+-10}=\frac{55}{-22}=\frac{5}{-2}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{5}{-2}.4=-10\\y=\frac{5}{-2}.\left(-5\right)=\frac{25}{2}\end{cases}}\)
c) Ta có :
2x + 5y = 10
\(\frac{x}{3}=\frac{y}{4}=\frac{2x}{6}=\frac{5y}{20}\)
Áp dụng tính chất dãy tỉ số bằng nhau , ta có :
\(\frac{x}{3}=\frac{y}{4}=\frac{2x}{6}=\frac{5y}{20}=\frac{2x+5y}{6+20}=\frac{5}{13}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{5}{13}.3=\frac{15}{13}\\y=\frac{5}{13}.4=\frac{20}{13}\end{cases}}\)
f) Ta có :
y - 2x = 5
4x = 5y \(\Rightarrow\frac{x}{5}=\frac{y}{4}=\frac{2x}{10}\)
Áp dụn tính chất dãy tỉ số bằng nhau , ta có :
\(\frac{x}{5}=\frac{y}{4}=\frac{2x}{10}=\frac{y-2x}{4-10}=\frac{5}{6}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{5}{6}.5=\frac{25}{6}\\y=\frac{5}{6}.4=\frac{10}{3}\end{cases}}\)
g) Ta có :
x + y = 60
\(\frac{x}{y}=\frac{9}{11}\Rightarrow\frac{x}{9}=\frac{y}{11}\)
Áp dụn tính chất dãy tỉ số bằng nhau , ta có :
\(\frac{x}{9}=\frac{y}{11}=\frac{x+y}{9+11}=\frac{60}{20}=3\)
\(\Rightarrow\hept{\begin{cases}x=3.9=27\\y=3.11=33\end{cases}}\)
G
15
G
11
MN giúp mk nhé
VT
0
7 tháng 10 2021
III. Complete each sentence so it means the same as the sentence above.
1. I didn’t go to school because I was sick.
-> I was sick, so I didn't go to school.
2. It will be good if you eat less meat and more vegetables.
->You should eat less meat and more vegetables.
3. He s playing computer games in his free time.
->His hobby is playing computer games in his free time.
4. I am interested in watching TV in the evening.-> I enjoy watching TV in the evening.
5. I think that learning English is important.->I find learning English important.
6. My brother enjoys coffee very much. -> Coffee is my brother's favorite drink.
7. What is the price of a plate of fried rice? -> How does a plate of fried rice cost?
8. This food has some meat and tofu. -> There is some meat and tofu in this food.
9. Chicken is my sister’s favorite food. (s) -> My sister s chicken.
10. There is sugar in many kinds of food. (have) -> Many kinds of food have sugar.
IV. Use the words given to write a paragraph about Huong’s hobby.
Huong is a student in class 7A at Quang Trung school. Collecting glass bottles is one of her favorite hobbies. She started her hobby when she was 10 years old. She often shares her/ the hobby with her sister. She finds her hobby interesting and useful. She feels happy when she looks at beautiful flower vases made from them. She will continue her hobby in the future because it helps save the environment.
V. Read and fill in the blanks with ONE word given in the box.(Tự làm)