<span>3x+4=y+5, then y+5=3x+4
It is called: reflexive property
-----------------------------
</span>
<span>x = y and y = 10, then x = 10
It is called: equality substitution property
</span>
3 buckets covers 90m x 80cm = 3 buckets for 90x0.8 = 3 for 72
x buckets covers 200m x 120cm = x buckets for 200x1.2 = x for 240
3/72 = x/240
720 = 72x
x =10 buckets of paint to cover 200mx120cm fence
1/10*(f-220) or 0.1(f-220)