Question

ROZWIĄŻ RÓWNANIA KWADRATOWE
a)(x-5)(x² + 5x + 25) = x(x² - 4x) - 124
b) (x² - 3x + 1)(x+2) = x³ - 2x - 1

Answer 1

a)
(x-5)(x² + 5x + 25) = x(x² - 4x) - 124 
x³+5x²+25x-5x²-25x-100=x³-4x²-124
x³+5x²+25x-5x²-25x-100-x³+4x²+124=0
4x²-1=0
(2x-1)(2x+1)=0

2x-1= 0
2x=1 | :2
x= 1/2

2x+1=0
2x=-1 | :2
x= -1/2

b).
(x² - 3x + 1)(x+2) = x³ - 2x - 1
x³-3x²+x+2x²-6x+2-x³+2x+1=0
-x²-3x+3=0
Δ= (-3)²-4 · (-1) ·3= 9 +12=21
√Δ= √21

= √21-3 / 2

= -3-√21 / 2