46.
a. (4568 + 3759) - (4563 + 3764)
= 4568 + 3759 - 4563 - 3764
= (4568 - 4563) + (3759 - 3764)
= 5 - 5
= 0
b. 25 . 16 - 25 . 12
= 25 . (16 - 12)
= 25 . 4
= 100
c. 930 : 15 - 310 : 5 + 196
= 62 - 62 + 196
= 0 + 196
= 196
d. 572 : 26 - 156 : 13
= 22 - 12
= 10
47.
a. x - 280 : 35 = 5 . 54
x - 8 = 270
x = 270 + 8
x = 278
Vậy x = 278
b. (x - 280) : 35 = 56 : 5
(x - 280) : 35 = 11,2
x - 280 = 11,2 . 35
x - 280 = 392
x = 392 + 280
x = 672
Vậy x = 672
c. x : 15 + 42 = 13 + 25 . 8
x : 15 + 42 = 13 + 200
x : 15 + 42 = 213
x : 15 = 213 - 42
x : 15 = 171
x = 171 . 15
x = 2565
Vậy x = 2565
d. (x - 128 + 20) : 192 = 0
x - 128 + 20 = 0
x = 128 - 20
x = 108
Vậy x = 108
e. 460 + 85 . 4 = (x + 200) . 4
(x + 200) . 4 = 460 + 340
(x + 200) . 4 = 800
x + 200 = 800 : 4
x + 200 = 200
x = 200 - 200
x = 0
Vậy x = 0
f. x + 5 . 2 - (32 + 16 . 3 : 16 - 15) = 0
x + 10 - (32 + 3 - 15) = 0
x + 10 - 20 = 0
x = 20 - 10
x = 10
Vậy x = 10
