. (2000-74*21)(200*608-121530)=(2000- 1554)(121 600-121530)=446*70=31 220
2. 68*307+642+47*690-304=20 876+642+32 430-304=53 644
3. 1001*78+22(906-799)=78 078+22*107=78 078+2354=80 432
4. 56*640-(11 258-27*34)+374 498=35 840-(11 258-918)+374 498=35 840-10 340+374 498=25 500+374 498=399 998
10-2(-х-7)=9
10-2х+14=9
24-2х=9
-2х=-15
х=7.5
S = pi*r*r - площадь. r = \/ S/pi - радиус.
S1 = 37,7. r = \/ 37,7 / 3,14 = 3,46.
S2 = 37,3. r = \/ 37,3 / 3,14 = 3,45.