Answer:
Steps For Solving Real World Problems
2. Highlight the important information in the problem that will help write two equations.
3. Define your variables.
4. Write two equations.
5. Use one of the methods for solving systems of equations to solve.
6. Check your answers by substituting your ordered pair into the original equations.
Let p be the prize of a pen and m the prize of a mechanical pencils. If you buy six pens and one mechanical pencil, you spend 6p+m. We know that this equals 9, because you get 1$ change from a 10$ bill.
Similarly, if you buy four pens and two mechanical pencils, you spend 4p+2m, which is 8$, because now you get a $2 change. Put these equation together in a system:

Now, if you multiply the first equation by 2, the system becomes

Subtract the second equation from the first:

Plug this value into the first equation to get

So it would be x12 to the 2nd power, kinda hard to explain but i really hope this helped