4x^2 - 8x <= 5
4x^2 - 8x - 5 <= 0
4x^2 - 8x - 5 = 0
D = 64+80=144 = 12^2
x1 = (8+12)/8 = 2,5
x2 = (8-12)/8 = -1/2
2x^2 + x + x + 1 >= 3
2x^2 + 2x - 2 >= 0
x^2 + x - 1 >= 0
D = 1 + 4 = 5
x1 = (-1 + sqrt5)/2
x2 = (-1 - sqrt5)/2
Sin 8x-Sin 6x+Cos 7x=(128 cos^7 x-224cos^5 x+112cos^3 x-14cosx)*sinx+64cos^7 x-112cos^5 x+56cos^3 x-7cosx=(-((-128)*cos^7 x+224cos^5x+(-112)*cos^3x+14cosx))*sinx+64cos^7x+(-112)*cos^5x+56cos^3x-7cosx=sin(8x)+cos(7x)-sin(6x)
(4,9-x):1,2=3
4,9-x=3*1,2
4,9-x=3,6
x=1,3
<span>4a^2-b^2+2a-b=</span>2а(2а-1) - b(b-1)