a) 7 . 52 - 6 . 42
= 7 . 25 - 6 . 16
= 175 - 96
= 79
b) 16 . 24 + 76 . 16 + (-1600)
= 16 . (24+76) + (-1600)
= 16 . 100 + (-1600)
= 1600 + (-1600)
= 0
#Hok_tốt
\(a,7\times5^2-6\times4^2=\)
\(=7\times25-6\times16\)
\(=175-96\)
\(=79\)
\(b,16\times24+76\times16+\left(-1600\right)=\)
\(=16\times\left(24+76\right)+\left(-1600\right)\)
\(=16\times100+\left(-1600\right)\)
\(=1600+\left(-1600\right)\)
\(=0\)