<span>9x^2-10a^3+6ax-15a^2x = (</span><span>9x^2+6ax) - (15a^2x</span><span>+10a^3) = 3х(3х+2а) - 5</span><span>a^2(</span>3х+2а) = (3х+2а)*(3х-5a^2)
(2a-b)^3-(2a+b)^3 = 8a^3-12a^2b+6ab^2-<span>b^3 - </span> 8a^3-12a^2b-6ab^2-b^3 = -24a^2b - 2b^3 = -2b*(12a^2+<span>b^</span>2)
1) D=64+84=148 (4)
2) [-1+-sqrt(1+24)]/4=[-1+-5]/4
x1=1 x2=-1.5 (4)
3) q=4*(-3)=-12
-p=-3+4=1
p=-1
ответ (2)
Решение
Cos^2(2x)-sin^2(2x)=1/2
cos4x = 1/2
4x = (+ -)arccos(1/2) + 2πn, n ∈ Z
4x = (+ -) (π/3) + 2πn, n ∈ Z
x = (+ -) (π/12) + πn/2, n ∈ Z
Sin⁴xCos²x - Cos⁴xSin²x = Cos2x
Sin²xCos²x(Sin²x - Cos²x) - Cos2x = 0
Sin²xCos²x * (- Cos2x) - Cos2x = 0
Cos2x(Sin²xCos²x + 1) = 0
Cos2x = 0 Sin²xCos²x + 1 = 0
2x = π/2 + πn , n ∈ z 1/4Sin²2x + 1 = 0
x = π/4 + πn/2 , n ∈ z Sin²2x = - 4 - решений нет
Ответ : π/4 + πn/2 , n ∈ z
16-8y+у²-у²-y=16-9y=16+9*1/9=17