Am nevoie de putin ajutor!

[tex] \it \left(1-\dfrac{1}{2}\right)(1+0,5) =\left(1-\dfrac{1}{2}\right) \left(1+\dfrac{1}{2}\right)= 1^2-\left(\dfrac{1}{2}\right)^2=1-\dfrac{1}{4}=\dfrac{3}{4} [/tex]