Bài 1 :
a) -( 34 - 218 ) + ( -66 - 18 - 315 )
= -34 + 218 - 66 - 28 - 315
= ( -34 - 66 ) + ( 218 - 18 ) - 315
= -100 + 200 - 315
= 100 - 315
= -215
b ) 45 . (-35) + 35 . 145 - 65
= 35 . ( -45 +145 ) - 65
= 35 . 100 - 65
= 3500 - 65
= 3435
c ) -3 .(-4)³ - 5 . (-50) - (-2021)⁰ - (-5)
= -3 . (-64) - 5 . (-56) + 1 + 5
= 192 + 280 + 6
= 478
d ) -3 - 17
= - (3 + 7 )
= -21
e ) 89 - (-67)
= 89 + 67
= 156
f ) 600 : [ ( -81 + 80 ) . (-5)² ]
= 600 : ( -1 . 25 )
= 600 : (-25)
= -24
Bài 2 :
a ) -56 + x = 23
x = 23 + 56
x = 79
b ) 2x - 9 = -23 + (-2)⁴
<=> 2x - 9 = -23 + 16
<=> 2x - 9 = -7
<=> 2x =2
<=> x = 1
c ) 34 + 2.( x - 5 )² = 66
<=> 2.( x - 5 )² = 32
<=> ( x - 5 ) ² = 16
<=> ( x - 5 ) ² = (4)²
<=> x - 5 = 4
<=> x = 9
Bài 3 :
a ) Ư(20) = { ±1 ; ± 2 ; ±4 ; ±5 ; ±10 ; ±20 }
Ư(-20) = { ±1 ; ±2 ; ±4 ; ±5 ; ±10 ; ±20 }
B(-25) = { -25 ; -50 ..... }
