Solution of the Problem , Water Bill
Let ' s write the water bill to be paid as a function dependent on x , where x is the amount of water consumed .
0≤x≤35 , f ( x ) = 29,04024 + 1,1 .( 0,6237 . x + 0,3128 . x ) f ( x ) = 29,04024 + 1,03015 . x 35 < x < 50 , f ( x ) = 29,04024 + 1,1 .[ 0,6237 . x + 0,3128.35 + ( x-35 ). 0,8462 ] f ( x ) = 29,04024 + 1,1 .( 0,6237 . x + 10,948 + 0,8462 . x -29617 ) f ( x ) = 29,04024 + 1,1 .( 1,4699 . x -18,669 ) f ( x ) = 8,50434 + 1,61689 . x x≥50 , f ( x ) = 29,0424 + 1,1 .[ 0,6237 . x + 0,3128.35 + 0,8462.15 + ( x-50 ). 1,4462 ] f ( x ) = 29,0424 + 1,1 .[ 0,6237 . x + 10,948 + 12,693 + 1,4462 . x – 72,31 ] f ( x ) = 29,0424 + 1,1 .( 2,0699 . x – 48,669 ) f ( x ) = -24,49566 + 2,27689 . x