Let's write out the problem with the triangles as "x" and the ovals as a number. Since there are 3 triangles and 5 boxes in the first box, the first box would be:
3x+5
In the other box, there are 11 ovals, so:
11
With this, they are equal, so:
3x+5=11
To solve this, move the 5 over onto the other side by subtracting 5 from each side:
3x+5-5 = 11-5
Then you have:
3x = 6
Now, divide doth sides by 3 to isolate x:
3x/3= 6/3
Now you're done!
x=2
Hope that helps.
