Expand `(1+x+x^2)^4` in powers of x.

Expand: (4/5x-2)^3

Expand: (2x-2/x)^3

Expand: (x+2y+5z)^2

Expand: (x-2y-3z)^2

Expand: (4x+3y)^3

Expand: (4x+5y)^3

If the coefficient of x^(3) and x^(4) in the expansion of (1+ax+bx^(2)) (1-2x)^(18) in power of x are both zero, then (a,b) is equal to

When the determinant |{:(cos2x,,sin^(2)x,,cos4x),(sin^(2)x,,cos2x,,cos^(2)x),(cos4x,,cos^(2)x,,cos 2x):}| expanded in powers of sin x, then the constant term in that expression is

Expand |(3,x),(x,1)|

Expand |(8x, 3), (2, 2)|