\(5x^2-19x-4\)
\(=\left(5x^2-20x\right)+\left(x-4\right)\)
\(=5x\left(x-4\right)+\left(x-4\right)\)
\(=\left(x-4\right)\left(5x+1\right)\)
\(5x^2-19x-4=5x^2+x-20x-4\)
\(=x\cdot\left(5x+1\right)-4\cdot\left(5x+1\right)\)
\(=\left(5x+1\right)\cdot\left(x-4\right)\)
Mk ko bt có đúng ko nữa:
\(5x^2-19x-4\)
\(=5x^2+x-20x-4\)
\(=x.\left(5x+1\right)-4.\left(5x+1\right)\)
\(=\left(5x+1\right).\left(x-4\right)\)
Rất vui vì giúp đc bạn !!!
5x^2 - 19x - 4
= 5x^2 + x - 20x - 4
= (5x^2 + x) - (20x + 4)
= x(5x + 1) - 4(5x + 1)
= (5x + 1)(x - 4)