7/15 simplified I’ve tried everything!!PLEASE ANSWER ASAP

Describe in detail how you would construct a 95% confidence interval for a set of 30 data points whose mean is 20 and population standard deviation is 3. be sure to show that you know the formula and how to plug into it. also, clearly state the margin of error.

Solve the equation using the given values: x= -2.5; y= -7.51. 2xy + 2x²

The area of a rectangle is 54x^9y^8 square yards.if the length of the rectangle is 6x^3y^4 yards,which expression represents the width of the rectangle in yards