Answer:x=750
Step-by-step explanation:
2/3(x)+ 1/4(x) + 375
(9/12)x - (3/12)x = 375
(6/12)x + 375
Simple,
so you have...
-5m=-35
You are trying to find m, so, to
isolate the variable divide both sides by -5:

m=7
Now, to check your work, plug in m.
-5(7)=-35
-35=-35
Thus, you know your answer is correct.
I believe it is D, stratified random sampling.
Hope this helps!!
I think the answer would be B :)