Can someone help me please

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

Aflower has 26 chromosomes. to create a new flower, how many chromosomes would a sperm cell have? what is this process called? part 2: within a flower cell that has 26 chromosomes, how many chromosomes would a cell that is created within the stem of a flower as it grows, have? what is this process called?