a) Ta có: 196.(a: a-1) + x = 58
Đặt a = m, ta có: 196.(m: m-1) + x = 58
=> 196m/(m-1) + x = 58
=> 196m + x(m-1) = 58(m-1)
=> 196m + xm - x = 58m - 58
=> (196 + x - 58)m = 58 - x
=> 138m = 58 - x
=> m = (58 - x)/138

b) Ta có: x.95 + x.4 + x = 129.8
=> 99x = 129.8
=> x = 129.8/99

c) Ta có: 59 + 27:x = 62
=> 27/x = 62 - 59
=> 27/x = 3
=> x = 27/3

d) Ta có: 2475: (x:8-216) = 1
=> 2475/(x/8 - 216) = 1
=> 2475 = x/8 - 216
=> x/8 = 2475 + 216
=> x/8 = 2691
=> x = 2691*8

e) Ta có: x:9.(2762-2759) = 207
=> x/9.(3) = 207
=> x/27 = 207
=> x = 207*27

f) Ta có: x.(21:3) = 2200 + 82
=> x.7 = 2200 + 82
=> x.7 = 2282
=> x = 2282/7

g) Ta có: 186.x - 85.x - x = 3400
=> 100.x - x = 3400
=> 99.x = 3400
=> x = 3400/99

h) Ta có: x.5 + x.7 - x - x = 27 + 73
=> 12x - 2x = 100
=> 10x = 100
=> x = 100/10