4\x-1=x\5. xне равен 1
20=x(x-1)
20-x9x-1)=0
20-x^2+x=0
x^2-x-20=0
D=(-1)^2-4*1*(-20)=81
x1=(1-9)/2=-4
x2=1+9/2=5
x-9/x=0. x не равно 0
x-9=0
x=9
25/y-y=0. y не рано 0
(25-y^2)/y=0
25-y^2=0
y^2=25
y1=5
y2=-5
-(COSX-SINX)^2+SQRT(2)(COSX-SINX)=0
3·tg 45°·tg 60° = 3·1·
= 3
2·cos 30°+ 6·cos 60° - 4·tg 45° = 2·
+ 6·
- 4·1 =
2·ctg 60° - 2·sin 60° = 2·
- 2·
= 2
·(
) =
(x+y+2)(x+y-2) = x^2+xy-2x+xy+y^2-2y+2x+2y-4 = x^2+y^2+2xy-4