问问问问问问(?
1方程组3∣x∣+2x+4∣y∣-3y=4∣x∣-3x+2∣y∣+y=7有___组解?
3∣x∣+2x+4∣y∣-3y=4....(1) ∣x∣-3x+2∣y∣+y=7......(2) x>=0,y>=0--->5x+y=4,-2x+3y=7--->x=5/17,y=43/17 x>=0,y<0---->5x-7y=4,-2x-y=7--->x=-45/19,舍去 x<0,y>=0---->-x+y=4,-4x+3y=7--->x=5,舍去 x<0,y<0----->-x-7y=4,-4x-y=7--->x=-5/3,y=-1/3 两组解