Suppose you were also asked to calculate a 90% confidence interval. What would change from the 95% confidence interval you calculated in question 3?The 90% confidence interval would be wider. The 90% confidence interval would be narrower. No change.

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.

twenty-six miles over two gallons because the proportion for the original 13 miles to one gallon would be written 13/1 and, doing the same thing to the top and bottom, i multiplied by 2 and got 26/2