bạn có thể nghe bài giảng của các thầy cô ở đây

um, cám ơn em đã nhắc nhở mọi người trên cộng đồng Olm

1: \(x^{2} + 9 - 16 y^{2} + 6 x\)

\(= \left(\right. x^{2} + 6 x + 9 \left.\right) - 16 y^{2}\)

\(= \left(\left(\right. x + 3 \left.\right)\right)^{2} - \left(\left(\right. 4 y \left.\right)\right)^{2} = \left(\right. x + 3 - 4 y \left.\right) \left(\right. x + 3 + 4 y \left.\right)\)

2: \(x^{2} - 9 + y^{2} + 2 x y\)

\(= \left(\right. x^{2} + 2 x y + y^{2} \left.\right) - 9\)

\(= \left(\left(\right. x + y \left.\right)\right)^{2} - 3^{2} = \left(\right. x + y + 3 \left.\right) \left(\right. x + y - 3 \left.\right)\)

3: \(x^{2} - 4 x + 4 - 9 y^{2}\)

\(= \left(\left(\right. x - 2 \left.\right)\right)^{2} - \left(\left(\right. 3 y \left.\right)\right)^{2} = \left(\right. x - 2 - 3 y \left.\right) \left(\right. x - 2 + 3 y \left.\right)\)

4: \(x^{2} - 4 x y + 4 y^{2} - 81\)

\(= \left(\left(\right. x - 2 y \left.\right)\right)^{2} - 81\)

\(= \left(\right. x - 2 y - 9 \left.\right) \left(\right. x - 2 y + 9 \left.\right)\)

5: \(25 - 10 x - 9 y^{2} + x^{2}\)

\(= \left(\right. x^{2} - 10 x + 25 \left.\right) - 9 y^{2}\)

\(= \left(\left(\right. x - 5 \left.\right)\right)^{2} - \left(\left(\right. 3 y \left.\right)\right)^{2}\)

=(x-5-3y)(x-5+3y)

6: \(9 y^{2} - 4 x^{2} + 4 x - 1\)

\(= 9 y^{2} - \left(\right. 4 x^{2} - 4 x + 1 \left.\right)\)

\(= \left(\left(\right. 3 y \left.\right)\right)^{2} - \left(\left(\right. 2 x - 1 \left.\right)\right)^{2}\)

=(3y-2x+1)(3y+2x-1)

7: \(x^{2} - 2 x - 4 y^{2} + 4 y\)

\(= \left(\right. x^{2} - 4 y^{2} \left.\right) - \left(\right. 2 x - 4 y \left.\right)\)

=(x-2y)(x+2y)-2(x-2y)

=(x-2y)(x+2y-2)

8; \(64 - 4 x^{2} + 12 x y - 9 y^{2}\)

\(= 64 - \left(\right. 4 x^{2} - 12 x y + 9 y^{2} \left.\right)\)

\(= 8^{2} - \left(\left(\right. 2 x - 3 y \left.\right)\right)^{2}\)

=(8-2x+3y)(8+2x-3y)

9: \(6 x^{2} + 6 y^{2} - 24 + 12 x y\)

\(= 6 \left(\right. x^{2} + 2 x y + y^{2} - 4 \left.\right)\)

\(= 6 \left[\right. \left(\left(\right. x + y \left.\right)\right)^{2} - 4 \left]\right. = 6 \left(\right. x + y - 2 \left.\right) \left(\right. x + y + 2 \left.\right)\)

10: \(9 x^{2} - 6 x + 1 - 25\)

\(= 9 x^{2} - 6 x - 24 = 3 \left(\right. 3 x^{2} - 2 x - 8 \left.\right)\)

\(= 3 \left(\right. 3 x^{2} - 6 x + 4 x - 8 \left.\right)\)

=3[3x(x-2)+4(x-2)]

=3(x-2)(3x+4)

11: \(x^{2} + 4 x + 4 - 49 y^{2}\)

\(= \left(\left(\right. x + 2 \left.\right)\right)^{2} - \left(\left(\right. 7 y \left.\right)\right)^{2}\)

=(x+2-7y)(x+2+7y)

12: \(a^{3} + 9 a - a b^{2} - 6 a^{2}\)

\(= a \left(\right. a^{2} - 6 a + 9 - b^{2} \left.\right)\)

\(= a \left[\right. \left(\left(\right. a - 3 \left.\right)\right)^{2} - b^{2} \left]\right.\)

=a(a-3-b)(a-3+b)

13: \(9 x^{2} + 6 x + 1 - 25\)

\(= 9 x^{2} + 6 x - 24\)

\(= 3 \left(\right. 3 x^{2} + 2 x - 8 \left.\right)\)

\(= 3 \left(\right. 3 x^{2} + 6 x - 4 x - 8 \left.\right)\)

=3[3x(x+2)-4(x+2)]

=3(x+2)(3x-4)

14: \(5 x^{2} - 10 x + 5 - 45 t^{2}\)

\(= 5 \left(\right. x^{2} - 2 x + 1 - 9 t^{2} \left.\right)\)

\(= 5 \left[\right. \left(\left(\right. x - 1 \left.\right)\right)^{2} - \left(\left(\right. 3 t \left.\right)\right)^{2} \left]\right.\)

=5(x-1-3t)(x-1+3t)

15: \(x^{2} - 36 y^{2} t^{2} - 10 x + 25\)

\(= \left(\right. x^{2} - 10 x + 25 \left.\right) - \left(\left(\right. 6 y t \left.\right)\right)^{2}\)

\(= \left(\left(\right. x - 5 \left.\right)\right)^{2} - \left(\left(\right. 6 y t \left.\right)\right)^{2}\)

=(x-5-6yt)(x-5+6yt)

16: \(x^{2} - 2 x y + y^{2} - 16 z^{2}\)

\(= \left(\left(\right. x - y \left.\right)\right)^{2} - \left(\left(\right. 4 z \left.\right)\right)^{2}\)

=(x-y-4z)(x-y+4z)

17: \(8 x^{2} - 16 x + 8 - 32 y^{2}\)

\(= 8 \left(\right. x^{2} - 2 x + 1 - 4 y^{2} \left.\right)\)

\(= 8 \left[\right. \left(\left(\right. x - 1 \left.\right)\right)^{2} - \left(\left(\right. 2 y \left.\right)\right)^{2} \left]\right. = 8 \left(\right. x - 1 - 2 y \left.\right) \left(\right. x - 1 + 2 y \left.\right)\)

18: \(4 x^{2} - 4 x + 1 - 81 a^{2}\)

\(= \left(\left(\right. 2 x - 1 \left.\right)\right)^{2} - \left(\left(\right. 9 a \left.\right)\right)^{2}\)

=(2x-1-9a)(2x-1+9a)

19: \(x^{2} - 6 x y + 9 y^{2} - 121\)

\(= \left(\left(\right. x - 3 y \left.\right)\right)^{2} - 1 1^{2}\)

=(x-3y-11)(x-3y+11)

20: \(12 x^{2} - 24 x + 12 - 3 y^{2}\)

\(= 3 \left(\right. 4 x^{2} - 8 x + 4 - y^{2} \left.\right)\)

\(= 3 \left[\right. \left(\left(\right. 2 x - 2 \left.\right)\right)^{2} - y^{2} \left]\right. = 3 \left(\right. 2 x - 2 - y \left.\right) \left(\right. 2 x - 2 + y \left.\right)\)

21: \(a^{2} + 6 a - b^{2} + 9\)

\(= \left(\right. a^{2} + 6 a + 9 \left.\right) - b^{2}\)

\(= \left(\left(\right. a + 3 \left.\right)\right)^{2} - b^{2} = \left(\right. a + 3 - b \left.\right) \left(\right. a + 3 + b \left.\right)\)

22: \(x^{3} - 4 x^{2} - 25 x y^{2} + 4 x\)

\(= x \left(\right. x^{2} - 4 x + 4 - 25 y^{2} \left.\right)\)

\(= x \left[\right. \left(\left(\right. x - 2 \left.\right)\right)^{2} - \left(\left(\right. 5 y \left.\right)\right)^{2} \left]\right.\)

=x(x-2-5y)(x-2+5y)

23: \(x^{2} - y^{2} + 14 x + 49\)

\(= \left(\right. x^{2} + 14 x + 49 \left.\right) - y^{2}\)

\(= \left(\left(\right. x + 7 \left.\right)\right)^{2} - y^{2}\)

=(x+7-y)(x+7+y)

24: \(a^{2} + 6 a - 4 b^{2} + 9\)

\(= \left(\right. a^{2} + 6 a + 9 \left.\right) - 4 b^{2}\)

\(= \left(\left(\right. a + 3 \left.\right)\right)^{2} - 4 b^{2}\)

=(a+3-2b)(a+3+2b)

dịch ra là mấy mù em nhé

anh có

hi, chào em