What 2 numbers add together to get negative 12 but add together to get negative 1

If you have the following equation, 2/3x+5/6-x=2-3/4x what would you multiply each term by to get rid of all the fractions

Ateacher wanted to buy a chair, a bookshelf, two tables and a desk. she spent $900 for all five items and the chair and the desk combined 70% of her total. if the bookshelf cost $50, how much did each of the tables cost?

Cherie works in retail and her weekly salary includes commission for the amount she sells. the equation s=400+0.15c models the relation between her weekly salary, s, in dollars and the amount of her sales, c, in dollars. interpret the slope of the equation.