`1.` `5x – 3{4x – 2[4x – 3(5x – 2)]} = 182`
`<=> 5x – 3{4x – 2[4x – 15x + 6]} = 182`
`<=> 5x – 3{4x – 2[-11x + 6]} = 182`
`<=> 5x – 3{4x + 22x – 12} = 182`
`<=> 5x – 3{26x – 12} = 182`
`<=> 5x – 78x + 36= 182`
`<=> -73x + 36 = 182`
`<=> -73x = 182 – 36`
`<=> -73x = 146`
`2.` Ta có `2( 5x - 8 ) - 3( 4x - 5 ) = 4( 3x - 4 ) + 11`
⇔ `2.5x - 2.8 - 3.4x - 3.( - 5 ) = 4.3x - 4.4 + 11`
⇔ `- 2x - 1 = 12x - 5 ⇔ 12x + 2x = - 1 + 5`
⇔ `14x = 4` ⇔ `x = 2/7`.
`3. 3x. ( x - 2) - 3. ( x^2 + 1 )= x + 1 - x (x - 2)`
`=> 3x^2 - 6x - 3x^2 - 3 = x+1 - x^2 + 2x`
`=> x^2 - 6x - 3 - 3x - 1 = 0`
`=> x^2 - 9x - 4 = 0`
`=> x = 7` hoặc `x = 2`
`4.` `5(3x+5)-4(2x-3)=5x+3(2x+12)+1`
`<=>` `15x+25-8x+12=5x+6x+36+1`
`<=>` `7x+37=11x+37`
`<=>` `7x=11x`
`<=>` `7x-11x=0`
`<=>` `-4x=0`
`<=>` `x=0`
`5.` ` - ( 7x - 7 ) + 3x. ( 2x - 1 ) - 2x. ( 3x + 15 ) = -42`
⇔` -7x + 7 + 3x. ( 2x - 1) - 2x. ( 3x + 15 ) = -42`
⇔` 7x + 7 + 6x^2 - 3x - 2x ( 3x + 15 ) = -42`
⇔` 7x + 7 + 6x^2 - 3x - 6x^2 - 30x = -42`
⇔` - 40x + 7 + 6x^2 - 6x^2 = -42`
⇔`-40x + 7 = -42`
⇔` -40x + 7 - 7 = -42 - 7`
⇔` -40x = -42 - 7 `
⇔`-40x = -49`
⇔ `$\frac{40x}{-40}$` `=` `$\frac{-49}{-40}$`
⇔`x = 49/40`
`6.` Ta có `4( 18 - 5x ) - 12( 3x - 7 ) = 15( 2x - 16 ) - 6( x + 14 )`
⇔ `4.18 - 4.5x - 12.3x - 12.( - 7 ) = 15.2x - 15.16 - 6.x - 6.14`
⇔ `72 - 20x - 36x + 84 = 30x - 240 - 6x - 84`
⇔ `156 - 56x = 24x - 324`
⇔ `56x + 24x = 156 + 324`
⇔ `80x = 480`
⇔ `x = 6.`
