okay so my answer may or may not be correct I am sorry if it is not.
<A= 52x+30
<B= 72x+40
<C= 92x+10
<D= 52x+20
I put <A and <B together and <C and <D together<A and <B :
52x+30 = 72x+40
-52 -52 30 = 20x+40 -40 -40
-10 = 20x/20 /20-0.5 = xwhen you put it into the equation as 52(-0.5)+30 you get 4, and when you put it in 72x+40 you also get four.
Now for <C and <D 92x+10 = 52x+20-52 -5240x+10 = 20 -10 -1040x = 10/10 /10x=4
