What is the exact area of this trapezoid?

Choose the graph that matches the following system of equations: 7x + 2y = −6 6x − 7y = 21 a line includes points negative 2 comma 4 and 0 comma negative 3. a line includes points 6 comma 2 and 0 comma negative 3 a line includes points 0 comma negative 3 and 6 comma 2. a line includes points negative 2 comma 1 and negative 3 comma 4 a line includes points 0 comma negative 3 and negative 1 comma 4. a line includes points 0 comma negative 3 and negative 1 comma 3 a line includes points 0 comma 3 and negative 1 comma negative 3. a line includes points 0 comma negative 3 and negative 2 comma 4.

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

Having a hard time understanding this question (see attachment).