f.4 math

44.f(x) =x^4-2x^3-7x^2+8x+12
=(x+1)(x^3-3x^2-4x+12)
=(x+1)(x-3)(x^2-4)
=(x-1)(x+2)(x-2)(x-3)
f(x)=0
x=1 or x=2 or x= -2 or x=3


45. x^4+6x^3-7x^2-36x+6=0
(x^4-7x^2+6)+(6x^3-36x)=0
(x^2-1)(x^2-6)+6x(x^2-6) =0
(x^2-6)(x^2+6x-1)=0
x=(+/-)root 6
or x=[-6(+/-)root 40]/2(1)(-1)