You can help with both if you want I just need help

What is x and y (use substitution? ) 5x+3y=38 and y=3x+8?

Design a number line containing five (5) points2.benin, one of the smallest countries in africa, has a total area of 43,475 square miles. the population of the country was recently estimated at 10,160,555. about 3,657,790 people live in rural areas. the country has only about 870 miles of surfaced roads. a. round off the total population to the nearest hundred thousand people. b. round off benin’s area in square miles to the nearest thousand. c. round off the number of miles of surfaced roads to the nearest ten. d. round off the number of people who live in rural areas to the nearest million.

Which expression can be used to determine the slope of the line that passes through the points -6, three and one, -9