Подробное решение 5,214^2-2,214^2
(5.214-2.214)(5.214+2.214)=7,428 × 3 = 22,284
A² -b² =(a -b)(a +b) 5.214² -2.214² =(5.214 -2.214)(5.214 +2.214) = =3 * 7.428 = 22.284