Question

Am nevoieee urgent
://

Answer 1

P(x)=x³-4x²+ax+b
P(1)=-.3
1³-4·1²+a·1+b=-3
1-4+a+b=-3
a+b=-3-1+4
a+b=0

P(-1)=7
(-1)³-4·(-1)²+a·(-1)+b=7
-1-4-a+b=7
-a+b=7+1+4
-a+b=12
avem sistemul
{a+b=0
{-a+b=12
   /  2b=12
b=12/2
b=6
din a+b=0  ⇒ a=-b
a=-6

B)  P(x)=x³-4x²-6x+6
P(x)+9x-6=x³-4x²-6x+6+9x-6=
x³-4x²+3x=x(x²-4x+3)=x(x-1)(x-3)

x²-4x+3=0
Δ=16-12=4
x1=(4-2)/2=1
x2=(4+2)/2=3