`bài 2 : a ) ( - 98 . 36 ) = - ( 98 . 36 ) = -3528`
`b ) 102 . ( -74 ) = - ( 102 . 74 ) = -7548`
bài 3
`a ) 32. ( - 64 ) . 64 .68 = -2048 . 4352 = -8912896`
`b) -54 . 76 + 16 . ( - 76 ) = ( - 54 + 16 ) . [ ( - 76 ) + 16 ] = -38`
`c) - 12 . 37 - 41 . 12 + 2 . ( -132 ) = -444 - 492 + -264 = -1200`
bài 4
`a ) 7 . ( 2x - 8 ) = 0`
` 2x - 8 = 7 : 0 `
`2x - 8 = 0 `
`2x = 0 + 8 `
`2x = 8 `
`x = 8 : 2 `
`x = 4 `
`b) (4-x ) . ( x+ 3 ) = 0`
`4 - x . x + 3 = 0 `
`4 - 2x + 3 = 0 `
`2x + 3 = 4 - 0 `
`2X + 3 = 4 `
`2x = 4 - 3 `
`2x = 1 `
`x = 2 : 1 `
`x = 2 `
`c ) - x ( 8 - x ) = 0`
`-x . 8 - x = 0 `
`-2x . 8 = 0 `
`-2x = 0 : 8 `
`-2x = 0 `
`x = -2 : 0 `
`x= 0 `
`d ) ( 3 x - 9 ) . ( 2x - 6 ) = 0 `
`3x - 9 . 2x - 6 = 0 `
`3 . 2x - 9 . 2 - 6 = 0`
`3 . 2x - 9 . 2 = 0 + 6 `
`3 . 2x - 9 . 2 =6 `
`3.2x - 9 = 6 : 2 = 3`
`3 . 2x = 3 + 9 `
`3 .2x = 12 `
` 2x = 12 : 3 `
`2x = 4 `
`x = 4 : 2 `
`x = 2 `
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