Question

$a)0,8(3) ^{2} - {( \frac{4}{3}) }^{2} =$

Answer 1

[0.8(3)] ^2 –(4/3)^2

=[(83-8)/90]^2 -16/9

=(75/90)^2 – 16/9

=(5/6)^2 – 16/9

=25/36 – 16/9

=(25-4•16)/36

= - 39/36

= - 13/12

Answer 2

0,8(3) = (83-8)/90 =75/90-5/6, relatia devine

(5/6)²-(4/3)²=(25/36)-(16/9), numitor comun 36

(25-64)/36= -39/36 =-13/12