A) 2y+z-z+2y=4y
Б) x+3-5x+7= -4x+10
В)2a-1+3-4=2a-2
Г) a+b-a+b-b+a=a+b
D)3m-2m+3+2-m=5
E)3y-1-2y+2+y-3=2y-2
( x - 4 )( x - 5 ) - x( x - 6 ) = 10
x^2 - 5x - 4x + 20 - x^2 + 6x = 10
- 9x + 20 + 6x = 10
- 3x = - 10
x = 10/3
x = 3 1/3
Х во второй степени или просто 2х
Sin(x)=10/11
cos(x)=sqrt(1-sin^2(x))=sqrt(1-100/121)=sqrt(21/121)=sqrt(21)/11
sin(2x)=2sin(x)cos(x)=2*(10/11)*(sqrt(21)/11)=20sqrt(21)/121
cos(2x)=1-2sin^2(x)=1-200/121=-79/121
tg(x)=sin(x)/cos(x)=(10/11)*(11/sqrt(21))=10/sqrt(21)
sqrt - корень