Question

                Tim x :  (12x-5).(4x-1)+(3x-7).(1-16x)=81

 

 

Answer 1

<=> 48x^2 - 12x - 20x + 5 + 3x - 48x^2 - 7 + 112x = 81 
<=> -32x + 115x = 81 + 2 
<=> 83x = 83 
=>x = 1

hc tốt

Answer 2

(12x - 5)* (4x - 1) + ( 3x - 7) * ( 1 - 16x ) = 81

 <=> 48x^2 - 12x - 20x + 5 + 3x - 48x^2 - 7 + 112x = 81
<=> -32x + 115x = 81 + 2 
<=> 83x = 83 
<=> x = 1

Answer 3

<=> 48x^2 - 12x - 20x + 5 + 3x - 48x^2 - 7 + 112x = 81 
<=> -32x + 115x = 81 + 2 
<=> 83x = 83 
<=> x = 1

hc tốt

Answer 4

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

\(\Leftrightarrow48x^2-32x+5+(-48)x^2+115x-7=81\)

\(\Leftrightarrow48x^2-32x+5-48x^2+115x-7=81\)

\(\Leftrightarrow(48x^2-48x^2)+(115x-32x)-(7-5)=81\)

\(\Leftrightarrow83x-2=81\Leftrightarrow83x=83\Leftrightarrow x=1\)

Vậy x = 1