Question

Rezolva in R ecuatiadeterminati ce tip de numere,rationale sau inrationale,sint solutiiele ei:

c)2.5(x-4)-6x=3-x
d)xla2-3x-10=0
e)2xla2+7x-8=0

Answer 1

Te ajut la c si d !
c) 2,5x - 10 -6x = 3 - x <=> -3,5x - 10 = 3 - x <=> -3,5x + x = 3 + 10 <=> -2,5x = 13 <=> - ( 25 / 10 ) x = 13 <=> x = - 13 * ( 2 / 5  ) <=> x = - 26 / 5  ∈ Q ;
d) a = 1 ; b = - 3 ; c = - 10 ; Δ = b^2 - 4ac => Δ = 49 ; x1 = ( - b + $\sqrt{delta} ) / (2a )$ => x1 = ( 3 + 7 ) / 2 => x1 = 5 ; analog x2 = - 2 ; ambele solutii sunt nr. rationale ;
Bafta !