Làm bài 5 hết luôn đi

`\color{#FFD700}{\text{♡}}` `\color{#FFD700}{\text{v}} \color{#FFE066}{\text{i}} \color{#FFEB99}{\text{t}} \color{#FFF3B0}{\text{c}} \color{#FFF8DC}{\text{t}} \color{#FFFFF0}{\text{e}}`

Đáp án+Giải thích các bước giải:

`1) 4x^4 - 4x^2 + 1`

`= (2x^2)^2 - 2 * (2x^2) * 1 + 1^2`

`= (2x^2 - 1)^2`

`2) 4x^2 - 12x + 9`

`= (2x)^2 - 2 * (2x) * 3 + 3^2`

`= (2x - 3)^2`

`3) 36 + x^2 - 12x`

`= x^2 - 12x + 36`

`= x^2 - 2 * x * 6 + 6^2`

`= (x - 6)^2`

`4) 1 - 10x + 25x^2`

`= 25x^2 - 10x + 1`

`= (5x)^2 - 2 * (5x) * 1 + 1^2`

`= (5x - 1)^2`

`5) x^4 + 81 + 18x^2`

`= x^4 + 18x^2 + 81`

`= (x^2)^2 + 2 * x^2 * 9 + 9^2`

`= (x^2 + 9)^2`

`6) 4x^2 - 20x + 25`

`= (2x)^2 - 2 * (2x) * 5 + 5^2`

`= (2x - 5)^2`

`7) x^2 + 4y^4 - 4xy^2`

`= x^2 - 4xy^2 + 4y^4`

`= x^2 - 2 * x * (2y^2) + (2y^2)^2`

`= (x - 2y^2)^2`

`8) x^2 + 10xy + 25y^2`

`= x^2 + 2 * x * (5y) + (5y)^2`

`= (x + 5y)^2`

`9) 9y^2 - 24xy + 16x^2`

`= 16x^2 - 24xy + 9y^2`

`= (4x)^2 - 2 * (4x) * (3y) + (3y)^2`

`= (4x - 3y)^2`

`--------`

`\text{Áp dụng hằng đẳng thức:}`

`** (a + b)^2 = a^2 + 2ab + b^2`

`** (a - b)^2 = a^2 - 2ab + b^2`