Question

What are the roots of the equation x square +256x-1296?

Answer 1

in such cases write prime factors of 1296
$1296 = 2 \times 2 \times 2 \times 2 \times 3 \times 3 \times 3 \times 3$
now we know that Multiplication of all these are 1296.
now try to make combination from these,so that addition or subtraction will become 256.
in this case no such value occurs.
so keep in mind that factor are not completely integral.
means roots are rational.