Thực hiện phép tính. c) ( 3/8 − 1 , 25 ) : ( 3/4 − 0 , 25 )^2

c) $(\frac{3}{8}-1,25):{(\frac{3}{4}-0,25)}^2$

$=(\frac{3}{8}-\frac{5}{4}):{(\frac{3}{4}-\frac{1}{4})}^2$

$=\left(\frac{-7}{8}\right):{\left(\frac{1}{2}\right)}^2=\left(\frac{-7}{8}\right):\frac{1}{4}$

$=\left(\frac{-7}{8}\right).4=\frac{-7}{2}$