(3sinx-5cos2x+1)/(8+7sin2x-2sin²x)=0
8+7sin2x-2sin²x≠0
8sin²x+8cos²x-2sin²x+14sinxcosx≠0
8cos²x+6sin²x+14sinxcosx≠0 /2cos²x≠0
3tg²x+7tgx+4≠0
tg²x=a
3a²+7a+4≠0
D=49-48=1
a1≠(-7-1)/6≠-4/3⇒tgx≠-4/3⇒x≠-arctg4/3+πn
a2≠(-7+1)/6≠-1⇒tgx≠-1⇒x≠-π/4+πn
3sinx-5cos2x+1=0
3sinx-5+10sin²x+1=0
10sin²x+3sinx-4=0
sinx=b
10b²+3b-4=0
D=9+160=169
b1=(-3-13)/20=-0,8⇒sinx=-0,8⇒x=(-1)^n+1*arcsin0,8+πn
b2=(-3+13)/20=1/2⇒sinx=1/2⇒x=(-1)^n *π/6+πn
А.4x=28
x=7
б.7x=9
x=9/7
в.-3x=18
x=-6
г.-5x=-25
x=5
д.13x=39
x=3
e.решения нет
1.а) 37.48 - 24.115 = 13.375
б) 0.481 * 3.5 = 1.6835
2. (17.88 * 0.4 - 3.052) : 410
17.88 * 0.4 = 7.152
7.152 - 3.052 = 4.1
4.1 : 410 = 0.01
3. 34% = 0.34
<span>122%= 1,22
</span><span> 71,6%= 0,716
</span>
4. V = a*b*c
V = 3.2 * 4 * 7.11 = 91.01
5. 1) 140 км - 20%
x=80%
(140*80)/20=x
x= 11200/20<span>
x=560</span>