Вправи: 337

337. Спростіть вираз.

a) n2-1n2+ n • (1 – 11-1n) = n2-1n2+ n • (1 – nn-1) = n2-1n2+ n • n-1- nn-1 = n+1•(-1)n(n+1) = –1n;

б) a4+c4 (a- c)2 – 2(1a-1c )2 = a4+c4 (a- c)2 – 2a2c2(a- c)2 = a4+c4- 2a2c2 (a- c)2 = (a2-c2)2(a- c)2 = (a- c)2(a+ c)2(a- c)2 = (a + c)².