Question

Rezolvati in R ecuatia (x²+4x)²-x²=4x+20

Answer 1

2x²+2•x²•4x-2x²=4x+20
2x²•4x=4x+20
8x³=4x+20
8x³-4x+20=0
4x•(x²-1)+20=0
x²-1=0=>x²=1=>x1=+1,x2=-1
=>4x•(-2)+30=0
-8x+30=0
-8x=-30
x=30/8=>x3=15/4
S={1,-1,15/4}