Ảnh ngược vậy tui dùng máy tính khó nhìn lắm
1) \(5x\left(3x+4\right)\)
\(=15x^2+20x\)
2) \(2020^2-2019^2\)
\(\left(2020+2019\right).\left(2020-2019\right)\\ =4039\)
3)
a) \(2x^2+4x\)
\(=2x\left(x+2\right)\)
b) \(x^2-xy-2x+2y\)
\(x\left(x-y\right)-2.\left(x-y\right)\\ =\left(x-2\right)\left(x-y\right)\)
1. \(5x\left(3x+4\right)=15x^2+20x\)
2. \(2020^2-2019^2=\left(2020+2019\right)\left(2020-2019\right)=4039.1=4039\)
3a/ \(2x^2+4x=2x\left(x+2\right)\)
b/ \(x^2-xy-2x+2y=\left(x^2-xy\right)-\left(2x-2y\right)=x\left(x-y\right)-2\left(x-y\right)=\left(x-y\right)\left(x-2\right)\)
1: \(5x\left(3x+4\right)=15x^2+20x\)
2: \(2020^2-2019^2=\left(2020-2019\right)\left(2020+2019\right)=4039\)
3:
a: \(2x^2+4x=2x\left(x+2\right)\)
b: \(x^2-xy-2x+2y\)
\(=x\left(x-y\right)-2\left(x-y\right)\)
\(=\left(x-y\right)\left(x-2\right)\)
