(3.5)^2-(16x2)^2=3^2x5^2-16^2x2^2=9x25-256x4=225-1024=-799
(39.42-37.42):42=[42.(39-37)]:42=42x2:42=1x2=2
2448:[190-(23-6)]=2448:[190-17)=2448:173=2448/173 nha Dương Ngọc Phuong Linh
\(a.3.5^2-16.2^2=3.25-16.4=75-64=11\)
\(b.\left(39.42-37.42\right):42=\left(39-37\right).42:42=2.1=2\)
\(c.2448:\left[190-\left(23-6\right)\right]=2448:\left(190-17\right)=2448:173=\frac{2448}{173}\)