1) 130-х+35=50
-х=50-35-130
-х=-115 (* -1)
х=115
2) у+87-130=200
у=200-87+130
у=243
3)50-х-3=20
-х=20+3-50
-х=-27 (* -1)
х=27
4)97+у+38=150
у=150-38-97
у=15
7,6/х = 2 1/9 / 2 4/9
2 1/9х = 7,6 * 2 4/9
19/9х = 76/10 * 22/9
19/9х = 1672/90
х = 1672/90 : 19/9
х = 1672/90 * 9/19
х = 88/10 = 8,8
Масштаб:
1) 1:100000
2)1:100
3)1:30000