Cual es el resultado de la siguiente división (– 1/3 a^2 b^5 – 1/2 a^5 b^4 + 2/5 a^3 b – 5a^2 b^7) / ( – 5a^2 b^2)

2-digit numbers less than 91 which are 1 less than a multiple of 10

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

3.17 scores on stats final. below are final exam scores of 20 introductory statistics students. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 57, 66, 69, 71, 72, 73, 74, 77, 78, 78, 79, 79, 81, 81, 82, 83, 83, 88, 89, 94 (a) the mean score is 77.7 points. with a standard deviation of 8.44 points. use this information to determine if the scores approximately follow the 68-95-99.7% rule. (b) do these data appear to follow a normal distribution? explain your reasoning using the graphs provided below.