x+56=70
"x" is a missing variable. That plus 56 will equal 70.
x is being added to 56. So, to find x, you subtract 56 on both sides.
x+56(-56)= 70(-56)
x=14
We can check this by making sure 14+56=70
14+56=70 <--- this is true
70=70
I hope this helps!
~kaikers
