1. (9у2-5у+4)-(4у2-7)= 9у2-5у+4-4у2+7=5у2-5у+11
2. 5х2(3х-х7)=15х3-5х9
3. 8х-(2х+4)=2(3х-2)
8х-2х-4= 6х-4
8х-2х-6х=4-4
х=0
4. 5с+10вс=5с(1+2в)
14х2у+28ху3=14ху(х+2у2)
1)2(1/2*sin3x+√3/2*cos3x)=0
2*sin(3x+π/6)=0
3x+π/6=πn
3x=-π/6+πn
x=-π/18+πn/3
2)2tgx-1/tgx +1=0
tgx≠0
2tg²x+tgx-1=0
tgx=a
2a²+a-1=0
D=1+8=9
a1=(-1-3)/4=-1⇒tgx=-1⇒x=-π/4+πn
a2=(-1+3)/4=1/2⇒tgx=1/2⇒x=arctg1/2+πn
10-4х<-3+9х
10+3-4х-9х<0
13-5х<0