Demuestra que la distancia dirigida del punto P1 (8,4) al punto P2 (8, y) es y- 4 cualquiera que sea el valor de y?

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%.

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?

Parabolas y=−2x^2 and y=2x^2 +k intersect at points a and b that are in the third and the fourth quadrants respectively. find k if length of the segment ab is 5.