How do spermatogenesis and oogenesis differ in terms of the number of gametes they produce?

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.

: -)

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.