please help it's due soon, make sure your answer are correct

An advertising company has arrived at the following statistics relating the amount of money spent, D, on advertising a certain product to the realized sale of that product in units sold, U. Dollarsspent 1,000 1,500 2,000 2,500 3,000 3,500 Units sold 520 540 592 600 605 615 Find the least squares line and use it to predict the sales when $4,000 is spent on advertising (Round the predicted number of units sold to the nearest integer.) 177d + 17009 4375 35 U(D) U(4,000) 638 X The following loads (in ounces) are suspended from a spring and the stated lengths (in inches) are obtained. Determine the spring constants and the equation that describes each spring. Predict the length of each spring when a weight of 15 ounces is suspended. (b)