please do in scheme

; Returns true if l and w are equal, and they are both greater than 0; false otherwise (define (isSquare l w) ;todo )

; Calculates x raised to the power y ; Assume that y is a non-negative number (i.e., y >= 0) (define (power x y) ; TODO: Fill this in 0 ; stub -- modify it accordingly )

; Returns the average of the values in the list ; and #f if the list is empty ; You may want to create a helper function for sum (define (avg lst) ; TODO: Fill this in 0 ; stub -- modify it accordingly )

; Calculate taxes paid based on income ; We'll use the following tax brackets for individual income ; income below $10,275 - 10% ; income from $10,276 to 41,775 - 12% ; income from 41,776 to 89,075 - 22% ; income from 89,076 to 170,050 - 24% ; income from 170,051 to 215,950 - 32% ; income from 215,951 to 539,900 - 35% ; income of 539,901 or more - 37% (define (tax income) ; TODO 0 )

; Returns a list containing only those items in lst that have exactly 3 digits ; Assume that all numbers in lst are positive ; For example (threeDigitsOnly '(123 4 65 785 2 900)) should return ; (123 785 900) (define (threeDigitsOnly lst) ; TODO: Fill this in '() ; stub -- modify it accordingly )