A student claims that for an organism to be called purebred the two alleles for a trait must be the same and that both alleles must be also
dominant. Do you agree? Explain.

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)

it takes hundreds of years to become stable.

if you have another question lmk.

i think its y= -4x-14