Question

rezolvati inecuatia (x-2)(4-x) > 0 ; x apartine Z​

Answer 1

(x-2)(4-x)>0

4x-x²-8+2x>0

-x²+6x-8>0 | * (-1) (cand inmultesti cu (-1)

x²-6x+8<0 se schimba semnul)

delta=36-32=4

x1=(6+2)/2=4

x2=(6-2)/2=2

=>x€(2,4)intersectat Z

=>x€{3}