What does a positive times a negative equal

Find the magnitude, correct to two decimal places, made by each of the following with positive direction of the x axis a) y= x the answer is 45° but i don’t know how

The difference of two numbers is 40. find the numbers if 0.3 parts of one number is equal to 37.5% of the other one.

The party planning committee has to determine the number of tables needed for an upcoming event. if a square table can fit 8 people and a round table can fit 6 people, the equation 150 = 8x + 6y represents the number of each type of table needed for 150 people.