Question

tính hợp lý

a. (47 . 27) . (-13) + 13 . (-53 - 27)

b. - 17 . (13 + 5) - 13 (-17 - 2)

Answer 1

\(a.\left(47\times27\right)\times\left(-13\right)+13\left(-53-27\right)\)

\(=1269\times\left(-1\right)\times13+13\left(-80\right)\)

\(=13\left(-1269\right)+13\left(-80\right)\)

\(=13\left[\left(-1269\right)+\left(-80\right)\right]\)

\(=13\left(-1349\right)\)

\(=-17537\)

\(b.-17\left(13+5\right)-13\left(-17-2\right)\)

\(=13\left(-17\right)+5\left(-17\right)-13\left(-17\right)+13.2\)

\(=0-85+26\)

\(=-59\)