Question

(2x-5)(4x-1)+(3x-7)(1-16x)=81

Answer 1

#)Góp ý :

Bạn ghi thiếu đề phải không ? (12x-5)(4x-1)+(3x-7)(1-16x) = 81 

#)Giải :

\(\left(12x-5\right)\left(4x-1\right)+\left(3x-7\right)\left(1-16x\right)=81\)

\(\Leftrightarrow12x\left(4x-1\right)-5\left(4x-1\right)+3x\left(1-16x\right)-7\left(1-16x\right)=81\)

\(\Leftrightarrow12x.4x-12x-20x+5-3x+3x.16x-7+7.16x=81\)

\(\Leftrightarrow48x^2-12x-12x-20+5+3x-48x^2-7+112x=81\)

\(\Leftrightarrow\left(48x^2-48x^2\right)+\left(112x-12x-20x+3x\right)-\left(7-5\right)=81\)

\(\Leftrightarrow83x=81+2\)

\(\Leftrightarrow x=1\)