(х-2)×2=2 (3х-10) 2х-4=6х-20
2х-6х=4-20 -4х=-16 (×-1) х =16:4
х=4 (4-2)×2=2 (3×4-10) 4=4
Ответ 4
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1)tg²x+ctg²x+3tgx+3cygx=-4
(tgx+ctgx)²-2tgxctgx+3(tgx+ctgx)+4=0 tgx*ctgx=1
(tgx+ctgx)²+3(tgx+ctgx)+2=0
tgx+ctgx=a
a²+3a+2=0
a1+a2=-3 U a1*a2=2
a1=-2⇒tgx+ctgx=-2
tgx+1/tgx+2=0
tg²x+2tgx+1=0 tgx≠0
(tgx+1)²=0⇒tgx=-1⇒x=-π/4+πn
a2=-1⇒tgx+ctgx=-1
tgx+1/tgx+1=0
tg²x+tgx+1=0 tgx≠0
tgx=t⇒t²+t+1=0
D=1-4=-3-решения нет
2)(1-сos2x)/2+(1-cos4x)/2=(1+cos6x)/2+(1+cos8x)/2
1-cos2x+1-cos4x=1+cos6x+1+cos8x
cos8x+cos6x+cos4x+cos2x=0
2cos5xcos3x+2cos5xcosx=0
2cos5x(cos3x+cosx)=0
2cos5x*2cos2xcosx=0
4cos5xcos2xcosx=0
cos5x=0⇒5x=π/2+πn⇒x=π/10+πn/5
cos2x=0⇒2x=π/2+πn⇒x=π/4+πn/2
cosx=0⇒x=π/2+πn
0,2<span>х^2</span> = 1,8
х^2 = 1,8/0,2
x^2 = 9
x1 = -3; x2 = 3
Ответ: 3; -3
4•sin30° + 2•cos30° - 6•cos60° - tg60° = 4•(1/2) + 2•(√3/2) - 6•(1/2) - √3 = 2 + √3 - 3 - √3 = 2 - 3 = - 1
<u><em>Ответ: - 1</em></u>