To build the same width Road on the rectangular ground with the width of 20m and the length of 30m, the remaining part of the lawn should be planted to make the lawn area 504cm square, how many meters is the width of the road

To build the same width Road on the rectangular ground with the width of 20m and the length of 30m, the remaining part of the lawn should be planted to make the lawn area 504cm square, how many meters is the width of the road

Let the width of the road be XM
（30－x）（20－x）＝551
x²－50x＋49＝0
（x－1）（x－49）＝0
X1 = 1, X2 = 49

As shown in the figure, a road with the same width is built on the rectangular ground with a width of 20 meters and a length of 32 meters (the shaded part in the figure), and the rest is planted with lawn. To make the lawn area 540 square meters, the width of the road is ()
A. 5m B. 4m C. 3M D. 2m

Let the width of the road be X. according to the meaning of the title, we get 20x + 32x-x2 = 20 × 32-540, sort out (x-26) 2 = 576, square root x-26 = 24 or x-26 = - 24, and solve x = 50 (rounding off) or x = 2, so the width of the road is 2m

As shown in the picture is a rectangular grassland, 16 meters long and 12 meters wide, with a road 2 meters wide in the middle. Calculate the area of grassland (shadow part)

The total length of the road is (16 + 12-2) meters, that is 26 meters. The area of the road is 26 × 2 = 52 (square meters), and the area of grassland is 16 × 12-52, = 192-52, = 140 (square meters). A: the area of grassland is 140 square meters