SOLUTION: C AND D ARE SETS OF REAL NUMBERS C{x|x<3} D{x|x< has a line under 9} C U D = C DOWNWARD U D = UNION AND INTERSECTION INTERVALS

Algebra ->  Linear-equations -> SOLUTION: C AND D ARE SETS OF REAL NUMBERS C{x|x<3} D{x|x< has a line under 9} C U D = C DOWNWARD U D = UNION AND INTERSECTION INTERVALS       Log On


   

Question 1085741: C AND D ARE SETS OF REAL NUMBERS
C{x|x<3}
D{x|x< has a line under 9}
C U D =
C DOWNWARD U D =
UNION AND INTERSECTION INTERVALS
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!
C is the set of real x such that +x+%3C+3+
That's everything to the left of the 3 below, excluding the 3 itself:
+%0D%0A+number_line%28+600%2C+-10%2C+10%2C++3%29%0D%0A
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D is the set of real x such that +x+%3C=+9+
That's everything to the left of the 9 below, including the 9 itself:
%0D%0A+number_line%28+600%2C+-10%2C++10%2C++9%29%0D%0A%0D%0A
{C} U {D} is the region to the left of the 9, including the 9 itself. Since D includes C, the union of the two sets coincides with D. Using interval notation, it would be written ( +-infinity+ , +9+ ] (open paren's means that endpoint is excluded, square bracket means that endpoint is included).
{C} intersect {D} is the region to the left of 3 (excluding the 3 itself) and coincides with set C. In interval notation: ( -infinity+, +3+ )
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