Question

rút gọn biểu thức

-3a-{-(-4a+5)+[-(5-6a)+(-12-4a)]}

 

Answer 1

Ta có:\(-3a-\left\{-\left(-4a+5\right)+\left[-\left(5-6a\right)+\left(-12-4a\right)\right]\right\}\)

\(=-3a-\left[4a-5+\left(6a-5-12-4a\right)\right]\)

\(=-3a-\left(4a-5+6a-5-12-4a\right)\)

\(=-3a-\left(6a-22\right)=-3a-6a+22=-9a+22\)

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