Let x be a side of the square. New perimiter of the square: 4(1+3090x) = 5:2x The percentage change is: 5 2X- 4x 124 X100%% = 4x X 100% = 4x 16. If the length of the sides of the square is decreased by 10%, what is the percentage change in the area of the square? Let x be a side of the square. New area of the square: (1- 10 % % x) * ( 1-10% x ) = The percentage change is: 17. Mr. Lai's salary is changed by +25 % from 2020 to 2021 and is changed by -40% from 2021 to 2022. Let $x be Mr. Lai's salary in 2022. (a) Express Mr. Lai's salary in 2021 in term of x. (b) Express Mr. Lai's salary in 2020 in term of x