5. Tìm x biết:
a) 456 + (x - 357) = 1362; b) (2345 - x) - 183 = 2014;
c) (x - 2002). 2006 = 0; d) 480 + 45. 4 = (x + 125) : 5 + 260;
e) 2005. (x - 2006) = 2005; g) [(x + 50) . 50 - 50] : 50 = 50.
Bài Làm:
a) 456 + (x - 357) = 1362
x - 357 = 1362 - 456
x = 1362 - 456 + 357
x = 1263
b) (2345 - x) - 183 = 2014
2345 - x = 2014 + 183
x = 2345 - 2014 -183
x = 148
c) (x - 2002). 2006 = 0
x - 2002 = 0
x = 2002
d) 480 + 45. 4 = (x + 125) : 5 + 260
(x + 125) : 5 = 660 - 260
(x + 125) : 5 = 400
x + 125 = 2000
x = 1875
e) 2005. (x - 2006) = 2005
x - 2006 = 1
x = 2007
g) [(x + 50) . 50 - 50] : 50 = 50
(x + 50). 50 - 50 = 2500
(x + 50). 50 = 2550
x + 50 = 51
x = 1