Răspuns:
Explicație pas cu pas:
c) x = 200+199•200 = 200•(1+199) = 200•200 = 200² = patrat perfect
d) x = n + n•(n-1) = n•(1+n-1) = n•n = n² = patrat perfect
e) x = √441 + √(42•43+43•44)/2 = 21 + √[43•(42+44)]/2} =
= 21+√(43•43) = 21+43 = 64 = 8² = patrat perfect
f) x = (3ⁿ⁺² - 3ⁿ⁺¹ - 2•3ⁿ)/3ⁿ = (3²•3ⁿ-3•3ⁿ-2•3ⁿ)/3ⁿ =
= 3ⁿ•(9-3-2)/3ⁿ = 4 = 2² = patrat perfect