\(a,3x^2y-6x=3x\left(xy-2\right)\)

\(b,x^2-4=x^2-2^2=\left(x-2\right)\left(x+2\right)\)

\(c,5x^2+5xy-x^2-2xy-y^2\)

\(=5x\left(x+y\right)-\left(x+y\right)\left(x+y\right)\)

\(=\left(x+y\right)\left(5x-x+y\right)\)

\(=\left(x+y\right)\left(4x+y\right)\)

1-are students allowed to talk in class?

2-Can I read this book?

3-Can I borrow your pencil to draw this picture?

4- can you turn on the tv?

5-playing soccer so he plays sports every day.

cố lơn bẹn, chữ xấu qué đọc k đựt

a, hông bt làm:>

\(b,3x^2-7x-6\)

\(=\left(3x^2-9x\right)+\left(2x-6\right)\)

\(=\left(x-3\right)\left(3x+2\right)\)

\(c,4x^2+4a\left(b-a\right)-b^2\)

\(=4x^2-4a\left(a-b\right)-b^2\)

\(=4x^2-4a^2+4ab-b^2\)

\(=\left(2x\right)^2-\left(4a^2-4ab+b^2\right)\)

\(=\left(2x\right)^2-\left[\left(2a\right)^2-4ab+b^2\right]\)

\(=\left(2x\right)^2-\left(2a-b\right)^2\)

\(=\left(2x-2a-b\right)\left(2x+2a-b\right)\)

\(d,x^4+4\)

\(=\left(x^2\right)^2+2^2\)

\(=\left(x^2+2\right)^2-2x^22\)

\(=\left(x^2+2\right)^2-4x^2\)

\(=\left(x^2+2\right)^2-\left(2x\right)^2\)

\(=\left(x^2+2+2x\right)\left(x^2+2-2x\right)\)

cố lơn cố lơn

tính ra rồi cộng trừ đơn thức , tự làm đuy:>

a, x=2, y=3

b,pthh:

\(Fe_2O_3+3H_2SO4\Rightarrow Fe_2\left(SO4\right)_3+3H_2O\)

3A

4B

5B

6C

7B

8C