`a) 2^603 = (2^3)^201 = 8^201`
`3^402 = (3^2)^201 = 9^201`
`8^201 < 9^201`
`=> 2^603 < 3^402`
`b) `
`A = 2 + 2^2 + 2^3 + ... + 2^2020`
`2A = 2^2 + 2^3 + 2^4 + .... + 2^2021`
`2A - A = 2^2021 - 2`
`A = 2^2021 - 2`
`=> 2(A + 2) = 2^(2x)`
`2(2^2021 - 2 + 2) = 2^(2x)`
`2 . 2^2021 = 2^(2x)`
`2^2022 = 2^(2x)`
`2022 = 2x`
`x = 2022 : 2 = 1011`