12/cos47+sin47=12+(2cos47*sin47)/2=12+sin94/2=24+sin94
1.5х(х+4)-х(7-0.5х)=0.5(10-2х)=
=1.5х+6х-7х+0.5х=5-х
=1.5х+6х-7х+0.5х+х=5
х=5
6 • 6 = 36 ( лет ) отцу
36 + Х = 4( 6 + Х )
36 + Х = 24 + 4x
3x = 12
X = 4 ( года )
Ответ через 4 года
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√2(sin2x•cosπ/4+cos2x•sinπ/4)+
√3cosx=sin2x-1
sin2x+cos2x+√3cosx=sin2x-1
cos2x+√3cosx+1=0
2cos²x+√3cosx=0
cosx(2cosx+√3)=0
1)cosx=0
x=π/2+πk
2)2cosx=-√3
cosx=-√3/2
x=±(π-√6)+2πk
x=±5π/6+2πk;k€Z