Help with the question plz

EXPLAIN TOO!

How can you find the magnitude of a vector, v = < x,y > , where the horizontal change is x and the vertical change is y?

More challenges: 1) factor out the indicated quantity.8mn² + 7mn - m : factor out the quantity -m2) factor the polynomial by grouping.2vw + 7cv + 14cw + 49c²3) factor completely using the difference of squares along with factoring by grouping.25v³ - 25v² - 4v + 44) factor the sum of cubes. 125x³ + 645) q³ + 27r³6) factor completely. use difference of squares.729p^6 - 6^67) solve the equation(7x + 4)(9x - 1) = 08) a. find the values of x for which f (x) = 0b. find f (0)f (x) = x² + 2x - 489) find the x and y-intercepts for the function defined by y = f (x)f (x) = (x + 3)(x + 4)(x - 1)²10) factor the trinomial completely by using any method. remember to look for a common factor first. 3v² - 2v - 16

Of 400 people at the school carnival, 95% are students and the rest are teachers. a. how many students are at the school carnival? b. if 55% of the students at the school carnival are boys, how many are girls? c. how many teachers are at the school carnival? d. if 35% of the teachers are male and the rest are female, how many female teachers are at the carnival?