\(2021+5\left[300-\left(17-7\right)^2\right]\)
\(=2021+5\left[300-10^2\right]\)
\(=2021+5\left[300-100\right]\)
\(=2021+5\cdot200\)
\(=2021+1000=3021\)
b) 2021 + 5 [300 - (17 - 7)2]
= 2021 + 5 [ 300 - 102]
= 2021 + 5 [ 300 - 100]
= 2021 + 5 . 200
= 2021 + 1000
= 3021