B1:TH phép tính( tính HL nếu có thể) 91 . (-347) + (-91) . 653 167 + (-252) + 52 + (-67) (-124).(-245) + 124. (-45) B2: Tìm X -32 - 4(x-5) = 0 (7-x) - (25 + 7) = -25 [(6x - 39) : 7] . 4 = 12 (x : 3 - 4) . 5 = -15 (3x - `2^4` ) . `7^3` = 2 . `7^4`

`B1:`

`91 . (-347) + (-91) . 653`

`=−31577−91×653`

`=−31577−59423`

`=-91000`

`---`

`167 + (-252) + 52 + (-67)`

`= 167−252+52−67 `

`= −85+52−67 `

`= −33−67`

`=-100`

`---`

(-124).(-245) + 124. (-45)

`= 30380+124×−45`

`=30380−5580`

`=24800`

`B2:`

`-32 - 4(x-5) = 0`

`<=> −4(x−5)=32 `

`<=>x−5=− 4/ 32` ​

`<=>x−5=−8`

`<=>x=−8+5`

`<=>x=−3`

Vậy `x=-3`

`---`

`(7-x) - (25 + 7) = -25`

`<=>7−x−25−7=−25`

`<=>7−x−7=0`

`<=>−x=0`

`<=> x=0`

Vậy `x=0`

`---`

`[(6x - 39) : 7] * 4 = 12`

`<=> [(6x - 39) : 7] . 4 = 12`

`<=> [(6x - 39) : 7] = 3`

`<=>``6x - 39 = 3 . 7`

`<=>6x-39=21`

`<=>6x=21+39`

`<=>6x=60`

`<=>x=60:6`

`<=> 10`

Vậy `x=10`

`---` 

`(x : 3 - 4) . 5 = -15`

`<=> x:3-4= -15:5`

`<=> x:3-4= -3

`<=> x:3= (-3)+4

`<=> x:3=1

`<=> x=1*3

`<=>x=3`

Vậy `x=3`

`---`

`(3x-2^4 )* 7^3 = 2*7^4`

`<=> (3x - 16) . 343 = 2 . 2401`

`<=>(3x - 16) . 343 = 4802`

`<=>3x - 16 = 4802 : 343 `

`<=>3x - 16 = 14`

`<=>3x = 14 + 16`

`<=>3x = 30`

`<=> x = 30 : 3`

`<=> x=10`

Vậy `x=10`