One reason would be if you did not know the answer so you could do
4-5=x
another reason would be if the problem gave you the answer but not one of the things to get the answer
4-x=-1
not sure if that is what you want but I hope this helped
Answer: 
Step-by-step explanation:
Given a System of linear equations, the solution of the system is the point 
in which the lines intersect, where "x" is the x-coordinate and "y" is the y-coordinate.
Having the following System of equations:
You can use the Elimination method to find the value of "x":
-Multiply the second equation by 3.
- Add the equations.
- Solve for "x".
Then, you get:
The proportional relationship should require they y-intercept and is then 0 and the linear relationship should be in a straight line to be a linear! Hope this helps!
Answer:
63
Step-by-step explanation:
just multiply all all the packs by 12 an then subtract 225 and then u divide that by 25 and u get 63
376.99 try that the formula is 2x3.14x5x12
