f(x)=4x-x^2-7
−21x^3y^4z^5-23x^7y^7z^3
4x-x^2-7
tan -2800degrees
f(x) = -2x(x-1)(x+2)
$$6x=\frac{x}{30}$$
f(x) = 3x^2 - 7x
tan 780degrees
5^2+2^2=x^2 then x=?
f(x) = (x+1)(x^2-10x+21)