(1)∵AB=8cm,BC=10cm, ∴重叠部分的长为(10-x),宽为[8-(x+1)], ∴重叠部分的面积=(10-x)[8-(x+1)]=(10-x)(7-x)=70-10x-7x+x2, =x2-17x+70, ∵8-(x+1)>0, 解得x<7, ∴x应满足的条件是:0≤x<7;
(2)方法一:S=10×8×2+x(x+1)×2-(x2-17x+70), =160+x2+x-x2+17x-70, =18x+90; 方法二:S=(10+x)(8+x+1)-x(x+1)×2, =(10+x)(9+x)-x2-x, =90+19x+x2-x2-x, =18x+90. |