Faci inmultirea fractiilor pe diagonala si rezulta :
( x - 1.4 ) ( x + 5.6 ) = 120
x² + 4.2x - 7.84 = 120
x² + 4.2x - 127.84 = 0
Acum rezolvi ecuatia de gradul al II - lea
Δ = b² - 4ac
Δ = 17.64 - 511.36
Δ = 529
√Δ = √529 = 23
Afli solutiile
x₁ = ( -b + √Δ ) / 2a ⇔ x₁ = 9.4
x₂ = ( -b - √Δ ) / 2a ⇔ x₂ = -13.6
Succes!