4b-2a -2(a-2b)
------------ = -------------- = -2*5= -10
5b+3a 5b+3a
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5a-10b 5(a-2b) 5
----------- = ------------- = ---- *5= 25/3
15b+9a 3(5b+3a) 3
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a²-4ab+4b² (a-2b)²
---------------------- = ------------ = 5²=25
9a²+30ab+25b² (3a+5b)²
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5b+3a 5b+3a
( -----------)³ = (-------------)³ = (-1/5)³= -1/125
2b-a -1*(a-2b)