The problem of combining similar items and removing brackets in mathematics of grade one in junior high school Known: | x-y-3 | + (a + B + 4) 178; = 0, find [(X-Y) 178; - 3 (Y-X)] / [2A + 2B - (a + b)]
∵:|X-Y-3|+(A+B+4)²=0
∴X-Y-3=0,A+B+4=0
∴X-Y=3,A+B=-4
[(X-Y)²-3(Y-X)]÷[2a+2b-(a+b)]=[(X-Y)²+3(X-Y)]÷(a+b)=﹙3²﹢3×3﹚÷﹙﹣4﹚=-4.5