15x - 8x = 105
7x = 105
x = 105/7
x = 15
Рубли-%
1)400-100
x-20
x=20*400/100=80
2)400+80=480
1) 3³-2⁴=27-
16=11
2)9³-9²=729+81=810
3) 8³:16²=512:256=2
4)(46-37)³ * 10³=9³ * 10³=729*1000=729000
55/7=(9×+2)/28
55/7 × 28=9×+2
220=9×+2
220-2=9×
×=218/9 =24 2/9
может 5/7??
5/7× 28=9×+2
20-2=9×
×=2