В) 10х2-(2х-3)(5х-1)=31
10х2-10х2+2х+15х-3=31
17х=34
х=2
г) (х-2)(х-3)-(х+2)(х-5)=0
х2-5х+6-х2-3х-10=0
-8х=4
х=0,5
(10 sin 15) / (sin 15) = 10
1) (4x)³+3·(4x)²·0.1y+3·4x·(0.1y)²+(0.1y)³=64x³+4.8x²y+1.2xy²+0.001y³
2) (0.2a)³+3·(0.2a)²·10b+3·0.2a·(10b)²+(10b)³=0.008a³+1.2a²b+60ab²+1000b³
3) (0.3b)³-3 ·(0.3b)² ·10c+3·0.3b·(10c)²-(10c)³=0.027b³-2.7b²c+90bc²-1000c³
Ответ:
1-2b s=ab s=2*b
2-2 s=2*1
вся фигура- s=2*(b+1)=2b+2
4cosx - 4sinx - 4sin2x = 0
4cosx - 4sinx - 8sinxcosx = 0 | : 8cosx
2 - 4tgx - tgx = 0
2 - 5tgx = 0
-5tgx = -2
tgx = 2/5
x = arctg2/5 + Pi*n, n € Z