Chọn đáp án đúng

1) I ____ a student

A. Are B. Is C. Am D. Do

2) My farther ______ me happy and comfortable

A. Make always B. Always make

C. Always makes D. Alway making

3) His student _______ German is class

A. Don't speak B. Doesn't speak

C. Not speak D. Do speak

4) Danny _______ to see his father on Sundays

A. Come B. Will comes

C. Do come D. comes

5) John ______ in a supermarket

A. Working B. Work

C. Does work D. Works

@Trần Thị Đào

My neighbourhood is in the centrel of Nghe An Province. You can see many shops, restaurants and stadiums. They are very big and beautiful. It has a lot of trees along the street. The food in here is very good. I like living in my neighourhood very much beacause in here I have many friendly peoples.
@Linh Trần

x + 16 \(⋮x+1\)
<=> x + 1 + 15 \(⋮x+1\)
<=> 15 \(⋮x+1\)
=> x + 1 \(\inƯ\left(15\right)=\left\{\pm1;\pm15\right\}\)
=> x = 0; -2; 14; -16 (thỏa mãn)
@Bảo Bình

a, x² - 0,25 = 0
<=> x² = 0,25
<=> x² = (0,5)²
<=> \(\left[{}\begin{matrix}x=0,5\\x=-0,5\end{matrix}\right.\)
b, \(\dfrac{8}{2x}=2\)
<=> 2.2x = 8
<=> 4x = 8
<=> x = 2
c, (2x - 1)³ = 8
<=> (2x - 1)³ = 2³
<=> 2x - 1 = 2
<=> 2x = 3
<=> x = \(\dfrac{3}{2}\)
d, (x - 2)² = 16
<=> (x - 2)² = 4²
<=> \(\left[{}\begin{matrix}x-2=4\\x-2=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\)
@Đặng Vũ Hoài Anh

e, \(\dfrac{4x-5}{2-3x}=\dfrac{3}{4}\)

<=> 4(4x - 5) = 3(2 - 3x)
<=> 16x - 20 = 6 - 9x
<=> 16x + 9x = 6 + 20
<=> 25x = 26
<=> x = \(\dfrac{26}{25}\)
@hoang thuy an

d, |\(\dfrac{3}{5}x+\dfrac{4}{3}\)| : \(\dfrac{2}{3}-0,5=1\dfrac{1}{2}\)

<=> |\(\dfrac{3}{5}x+\dfrac{4}{3}\)| : \(\dfrac{2}{3}-\dfrac{1}{2}=\dfrac{3}{2}\)

<=> |\(\dfrac{3}{5}x+\dfrac{4}{3}\)| : \(\dfrac{2}{3}=2\)

<=> |\(\dfrac{3}{5}x+\dfrac{4}{3}\)| = \(\dfrac{4}{3}\)

<=> \(\left\{{}\begin{matrix}\dfrac{3}{5}x+\dfrac{4}{3}=\dfrac{4}{3}\\\dfrac{3}{5}x+\dfrac{4}{3}=-\dfrac{4}{3}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\dfrac{3}{5}x=0\\\dfrac{3}{5}x=-\dfrac{8}{3}\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x=0\\x=-\dfrac{40}{9}\end{matrix}\right.\)

@hoang thuy an

c, -\(\dfrac{3}{2}-\dfrac{1}{4}x=1\dfrac{1}{3}-0,2x\)

<=> -\(\dfrac{3}{2}-\dfrac{1}{4}x=\dfrac{4}{3}-\dfrac{1}{5}x\)

<=> -\(\dfrac{1}{4}x+\dfrac{1}{5}x=\dfrac{4}{3}+\dfrac{3}{2}\)

<=> -\(\dfrac{1}{20}x=\dfrac{17}{6}\)

<=> x = -\(\dfrac{170}{3}\)

@hoang thuy an

b, \(\dfrac{4}{5}-\dfrac{3}{4}:x=0,3\)

<=> \(\dfrac{4}{5}-\dfrac{3}{4}:x=\dfrac{3}{10}\)

<=> \(\dfrac{3}{4}:x=\dfrac{1}{2}\)

<=> x = \(\dfrac{3}{2}\)

@hoang thuy an

Cách nữa nè !

x^2-x-12

=(x^2-9)-(x+3)

=(x-3)(x+3)-(x+3)

=(x+3)(x-4)

A = \(\dfrac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\dfrac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3-5^9.14^3}\)

= \(\dfrac{2^{12}.3^5-\left(2^2\right)^6.\left(3^2\right)^2}{\left(2^2\right)^6.3^6+\left(2^3\right)^4.3^5}-\dfrac{5^{10}.7^3-\left(5^2\right)^5.\left(7^2\right)^2}{\left(5^3\right)^3.7^3-5^9.\left(2.7\right)^3}\)

= \(\dfrac{2^{12}.3^5-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^5}-\dfrac{5^{10}.7^3-5^{10}.7^4}{5^9.7^3-5^9.2^3.7^3}\)

= \(\dfrac{2^{12}.3^4.\left(3-1\right)}{2^{12}.3^5.\left(3+1\right)}-\dfrac{5^{10}.7^3.\left(1-7\right)}{5^9.7^3.\left(1-2^3\right)}\)

= \(\dfrac{2}{3.4}-\dfrac{5.6}{7}\)

= \(\dfrac{2}{12}-\dfrac{30}{7}\)

= \(-\dfrac{173}{42}\)

@Trương Gia Kiệt