Question

help me help me help me
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Answer 1

Answer:

4/5+(2/5+(-3/4))

= 4/5+(2×4+(-3)×5)/20

= 4/5+(8+(-15))/20

= 4/5+(-7)/20

= 4×4+(-7)×1/20

= 16+(-7)/20

= 10/20=1/2

(4/5+2/5)+(-3/4)

= 6/5+(-3/4)

= 6×4+(-3)×5/20

= 28-(-15)/20

= 28+15/20

= 43/20

= 2 1/20

therefore a+(b+c) not equal to (a+b)+c