Can anyone describe the errors with the problems? For example the first answer is they did not distribute the negative

What is the square root of 45? (step by step working plz)

What is the multiple zero and multiplicity of f(x) = (x ? 3)(x ? 3)(x + 5)? multiple zero is 3; multiplicity is 2 multiple zero is 5; multiplicity is 1 multiple zero is ? 5; multiplicity is 1 multiple zero is ? 3; multiplicity is 2

:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?