nhiều quá nên chỉ làm 3-4 ý thôi còn lại e tự lm nhs
\(1,\) \(a^2-4b^2=a^2-\left(2b\right)^2=\left(a-2b\right)\left(a+2b\right)\)
\(3,\) \(a^2-25=a^2-5^2=\left(a-5\right)\left(a+5\right)\)
\(2,\) \(\)\(4a^2-b^2=\left(2a\right)^2-b^2=\left(2a-b\right)\left(2a+b\right)\)
\(4,\) \(25x^2-1=\left(5x\right)^2-1^2=\left(5x-1\right)\left(5x+1\right)\)
\(5,x^2-9=x^2-3^2=\left(x-3\right)\left(x+3\right)\)
... tương tự
1) \(a^2-4b^2=\left(a-2b\right)\left(a+2b\right)\)
2) \(4a^2-b^2=\left(2a-b\right)\left(2a+b\right)\)
3) \(a^2-25=\left(a-5\right)\left(a+5\right)\)
4) \(25x^2-1=\left(5x-1\right)\left(5x+1\right)\)
5) \(x^2-9=\left(x-3\right)\left(x+3\right)\)
6) \(9x^2-1=\left(3x-1\right)\left(3x+1\right)\)
7) \(121-x^2=\left(11-x\right)\left(11+x\right)\)
8) \(64x^2-9=\left(8x-3\right)\left(8x+3\right)\)
9) \(81x^2-25=\left(9x-5\right)\left(9x+5\right)\)
10) \(144x^2-81=\left(12x-9\right)\left(12x+9\right)\)
11) \(36y^2-49x^2=\left(6y-7x\right)\left(6y+7x\right)\)
12) \(196x^2-4y^2=\left(14x-2y\right)\left(14x+2y\right)\)
13) \(49x^2-25y^2=\left(7x-5y\right)\left(7x+5y\right)\)
14) \(100x^2-9y^2=\left(10x-3y\right)\left(10x+3y\right)\)
15) \(x^4-4y^2=\left(x^2-2y\right)\left(x^2+2y\right)\)
16) \(\dfrac{1}{4}x^2-y^2=\left(\dfrac{1}{2}x-y\right)\left(\dfrac{1}{2}x+y\right)\)
17) \(\dfrac{1}{4}x^2-\dfrac{1}{9}y^2=\left(\dfrac{1}{2}x-\dfrac{1}{3}y\right)\left(\dfrac{1}{2}x+\dfrac{1}{3}y\right)\)
18) \(\dfrac{4}{9}x^4-\dfrac{25}{4}=\left(\dfrac{2}{3}x^2-\dfrac{5}{2}\right)\left(\dfrac{2}{3}x^2+\dfrac{5}{2}\right)\)
19) \(25x^2-\dfrac{1}{4}y^2=\left(5x-\dfrac{1}{2}y\right)\left(5x+\dfrac{1}{2}y\right)\)
20) \(\dfrac{1}{25}-36x^2=\left(\dfrac{1}{5}-6x\right)\left(\dfrac{1}{5}+6x\right)\)