set theory
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e + t + m + x = 180 e + x = 90 t + x = 120 m + x = 150
how shuld i proceed
four variable , four unknowns a matrix might be fun 1 0 0 1 90 0 1 0 1 120 0 0 1 1 150 1 1 1 1 180
r4 -> r4 -r1 -r2 -r3 1 0 0 1 90 0 1 0 1 120 0 0 1 1 150 0 0 0 -2 180-90-120-150 r4 -> r4/-2 1 0 0 1 90 0 1 0 1 120 0 0 1 1 150 0 0 0 1 (180-90-120-150)/-2
by the way uncle i dont understand matrix
\[|A\cap B| = |B\cap C| = |A \cap C| = |A \cap B\cap C|\]But\[|A \cup B \cup C| = |A|+|B|+|C|-|A\cap B| - |B\cap C| - |A\cap C| + |A\cap B \cap C|\]\[\Rightarrow 180 = 90+120+150 - 2x\]\[\Rightarrow x = 90\]
from the big equation e + t + m + x = 180 take away the other equations e + x = 90 t + x = 120 m + x = 150 and solve for x
parthkohli how did u get 2x \(\Rightarrow 180 = 90+120+150 - \color{red}{2x}\)
\[|A\cap B| = |B\cap C| = |A \cap C| = |A \cap B\cap C| = \color{red}x \]
but i still don't understand how this become equal with the three \(|A\cap B| = |B\cap C| = |A \cap C| =\color{red}{ |A \cap B\cap C|}\)
no one was faced with exactly two problems |dw:1454425342783:dw|
ok
thnks
i have a question why can't \(x=0\) as \(|A\cap B| = |B\cap C| = |A \cap C| = 0\)
Exactly two intersections \(\ne\) At least two two intersections And concluding from the above, we can say that if A and B intersect, C must also intersect there. Which is why I wrote that.
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