What is the solution to this system of equations? x+y=2 y-7=2 x+y-7=3

Can someone me my sister? she is in third grade. 50 points and brainlist! ones that are not answered. plz and thx!

Given the following sampling distribution of one mean with a sample size 49, from a normally distributed population, find the population standard deviation, o.79828588912497

What are the solutions of the equation? z^2 + 11z + 24 = 0 a. 8, -3 b. 8, 3 c. -8, -3 d. -8, 3