Question

a.W(x)=9x3 - 4x2 - 27x + 12
b.W(x)=7x3 + 2x2 - 21x – 6
c.W(x)=x6 - x5 - x2 + x
d.W(x)=2x4 + x3 + 4x2 + x + 2
e.W(x)=x3 - 7x + 6

Answer 1

a.W(x)=9x³ - 4x² - 27x + 12
9x³-4x²-27x+12=0

x²(9x-4)-3(9x-4)=0

(x²-3)(9x-4)=0

x²-3=0 lub 9x-4=0

x²=3         9x=4|:9

x=√3          x=4/9

b.W(x)=7x³ + 2x² - 21x – 6

7x³ + 2x² - 21x – 6=0

x²(7x+2)-3(7x+2)=0

(x²-3)(7x+2)=0

x²-3=0 lub 7x+2=0

x²=3          7x=-2|:7

x=√3           x=-2/7

c.W(x)=x⁶ - x⁵ - x² + x

x⁶ - x⁵ - x² + x=0

x⁵(x-1)-x(x-1)=0

(x⁵-x)(x-1)=0

x⁵-x=0 lub x-1=0

x⁵=x|:⁵      x=1

x=x⁻⁴

d.W(x)=2x⁴ + x³ + 4x² + x + 2

2x⁴ + x³ + 4x² + x + 2=0
x³(x+1)+(4x²+x+2)=0

x³=0 lub x+1=0   4x²+4+2=0

x=0        x=-1     Δ=-31<0 brak rozwiązania
e.W(x)=x³ - 7x + 6

x³-7x+6=0

x(x²-7)+6=0

x=0   x²-7=0    6=0 sprzeczność