f) 33.( 139 – 17) – 39.( 133 –17)
\(=33.139-33.17-39.133+39.17\)
\(=33.\left(100+39\right)-39.\left(100+33\right)+17.\left(-33+39\right)\)
\(=33.100+33.39-39.100-39.33+17.6\)
\(=100.\left(33-39\right)+17.6\)
\(=100.\left(-6\right)+17.6\)
\(=\left(-6\right).\left(100-17\right)\)
\(=\left(-6\right).83=498\)
Nhầm phải là -498 nha bạn