5ctg(3π+π/2+a)/4ctga=5ctg(π/2+a)/4ctga=-5tga/4ctga=-5/4*tg²a
a=5π/4
-5/4*tg²(π+π/4)=-5/4*tg²π/4=-5/4*1=-1,25
(m²-2m)²-1 = (m² - 2m - 1)(m²-2m+1)
16-(m² +4m)² = 4^2 -(m² +4m) = (4 - m²- 4m)(4 + m² + 4m)
Y = 3x^2 - 7x - 6
y = 0
3x^2 - 7x - 6 = 0
D = 49 + 72 = 121 ; V D = 11
x1 = ( 7 + 11 ) : 6 = 3
x2 = ( 7 - 11 ) : 6 = - 2/3
x = 0
y = - 6
Ответ ( 0 ; - 6 ) ; ( 3 ; 0 ) ; ( - 2/3 ; 0 )
A) 3х/2у.
Б) 5у/у(у-5) = 5/у-5.
В) 3(а-б)/(а-б)(а+б) = 3/а+б.