Question

$a=2*(8+ \sqrt{18}) -3*(4+ \sqrt{8} )$ este numar intreg .

Answer 1

a=2(8+√8))-3(4+√8)∈Z
a=16+2√18-12-3√8
a=16+6√2-12-6√2(6√2 se reduc)
a=4∈ Z
REZOLVAREA

Answer 2

a=2(8+√18))-3(4+√8)
a=16+2√18-12-3√8
a=16+6√2-12-6√2
a=16-12
a=4
4 apartine lui Z deci s-a demonstrat