Question

What kind of genotypes and phenotypes will result from crosses of dominant red and recessive white flowers

Answer 1

Okay you have 2 phenotypes : Red and White
Let's say red=C and white=c, dominant is the capital and dominant is the lowercase.

You have 3 genotypes, CC, Cc and cc
2 of the same = homozygous and 2 different is heterozygous.
When at least 1 dominant allele is in the genotype, it will express the dominant trait.
So CC = Red phenotype
Cc is also red
cc = white

Recessive always needs to be homozygous.

In your case you have 2 possible combination. We don't know if the red flower is heterozygous of homozygous. So i'll make 2 punnett squares:

Answer 2

bro Answer will be different in case of incomplete Dominance(ex Mirabilis Jalapa)