Question 1208386
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You are correct. Anything inside set A is also in set B.
It might help to highlight the items you want to focus on.
A = {<font color=red>x</font>, <font color=red>x + 1</font>, <font color=red>x + 2</font>}
B = {a, b, c, <font color=red>x</font>, <font color=red>x + 1</font>, <font color=red>x + 2</font>}


This is what the <a href="https://en.wikipedia.org/wiki/Euler_diagram">Euler Diagram</a> would look like
{{{
drawing(400,400,-5,5,-5,5,
circle(0,0,4),
circle(-1,0,2),
locate(3,3,"B"),
locate(1,1,"A"),
locate(0,0,"x"),
locate(-2.5,0.5,"x+1"),
locate(-1.5,-0.5,"x+2"),
locate(2,-1.5,"a"),
locate(0.6,-1.5-0.5,"b"),
locate(0.6+0.6,-1.5-0.9,"c")
)
}}}
circle A is entirely inside circle B.
x,x+1,x+2 are in circle A. By extension they are also in circle B.
a,b,c are in circle B, but outside circle A.
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