解方程X X= 2X + = 70%X + 20%X = 3.6X=20 25% + 10X = X - 15%X = 68XX121 5X3 X126X5 =13.4 3X=X= XX= 4X6=2 X= X = X = X = 4x3 9 = 29 x + x = 4X21=4 6X5 =13.4 X-X= 46385X= X= X=X=12 X= X=X= X-0.25= =30% 4+0.7X=102 X+X=42 X+X=105 X-X=400 X-0.125X=8 = X+X=18 X( + )= x0.375x= x+=4 XX12 5 X2.4580.365- x = (x- 4.5) = 7 x- 25%x = 10x- 0.8x = 16+6 20 x 8.5= 1.5 x- x -4= 21 X25%X=90 XX= (1)+2.4=6 (2)3.5: =5:4.2 (3)1.8=2.4(4)= (5)631.8=7.2 (6)175=2.4+3 (7)= (8) = (9)12.62=8(10)= (11)=