1) 4 * (2х - 6) = 4х - 4 2) - 9у + 3 = 3 * (8у + 45)4 * 2х - 4 * 6 = 4х - 4 - 9у + 3 = 3 * 8у + 3 * 458х - 24 = 4х - 4 - 9у + 3 = 24у + 1358х - 4х = - 4 + 24 - 9у - 24у = 135 - 34х = 20 - 33у =132х = 20 : 4 у = 132 : (- 33)х = 5 у = - 4 3) 20 + 5х = 44 + х 5х - х = 44 - 20 4х = 24 х = 24 : 4 х = 6
1) 4 * (2х - 6) = 4х - 4 2) - 9у + 3 = 3 * (8у + 45)4 * 2х - 4 * 6 = 4х - 4 - 9у + 3 = 3 * 8у + 3 * 458х - 24 = 4х - 4 - 9у + 3 = 24у + 1358х - 4х = - 4 + 24 - 9у - 24у = 135 - 34х = 20 - 33у =132х = 20 : 4 у = 132 : (- 33)х = 5 у = - 4 3) 20 + 5х = 44 + х 5х - х = 44 - 20 4х = 24 х = 24 : 4 х = 6
x1=πn,n∈z
3π<πn<4π
3<n<4
нет решения
6cos²x-11cosx+4=0
cosx=a
6a²-11a+4=0
D=121-96=25
a1=(11-5)/12=1/2⇒cosx=1/2⇒x=11π/6+2πk,k∈z
3π<11π/6+2πk<4π
18<11+12k<24
7<12k<13
7/12<k<13/12
k=1⇒x=11π/6+2π=23π/6
a2=(11+5)/12=4/3⇒cosx=4/3>1 нетрешения
2)2сos²x+10sin2xcos2x+4sin²x+4cos²x=0/cos²x
4tg²x+10tgx+6=0
tgx=a
2a²+5a+3=0
D=25-24=1
a1=(-5-1)/4=-1,5⇒tgx=-1,5⇒x=-arctg1,5+πn
x=2π-arctg1,5
a2=(-5+1)/4=-1⇒tgx=-1⇒x=-π/4+πk,k∈z
x=3π/4
3)3cos²x+5sinxcosx+2cos²x=0
5cosx*(cosx+sinx)=0
cosx=0⇒x=π/2+πn,n∈z
x=5π/2
cosx+sinx=0/cosx
tgx+1=0
tgx=-1⇒x=-π/4+πm,m∈z
x=7π/4