I need some explanations for these problems:

1)the difference of a number and its square is 56. find the number.My teacher said it was 5/3. I want to ask how did he got that, please provide an equation.

2) The altitude of a traingle is 2m less than the base. The area of the triangle is 84m^2. FIND the base.

3) Theresa is crocheting an afghan that is already 30in. wide by 40in. long. If she continues to crochet by increasing the width and the length by then same number of inches until the afghan's area is doubled, what will be the new dimensions?

4) The height, h, of a riht circular cylinder of a given volume is inversely proportional to the square of the radius, r. Translate each statement into a formula. Use K as the constant of varation where needed

Please, I really need help and exaplanation along with some equations FAST! Thanks!