Find the product.
(9a^2 +8b) (a^2 - b)

Adepartment store purchases screen-printed t-shirts at a cost of $5 per shirt. they mark up the price 150% (making the selling price 250% of the store's purchase price) and put them on the sales floor. every month that a t-shirt doesn't sell, the store reduces the selling price by 25%.

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827

What is the y-intercept of the line with the equation 3x + 4y = 12?