:(0.5x+20)+x+(3x-80)=507

:(0.5x+20)+x+(3x-80)=507 3x*x=1600+x*x-80x (0.5x+3)×80%-x=9 求x 通分:x+4/x^2-8x+15,x-5/x^2+x-12,x-3/x^2-x-20 x-0.3x-0.5x=20 请问,(3)80+x>3x x 0.5x+20=3*(65-x) *-----------------------------------------------*| 6 4 X | 8 X X | X X 5 || X X X | X X X | X 7 8 || X X X | X X X | X X X ||---------------+---------------+--------------- || X X X | X X X | 5 1 X || X X X | X 6 X | X X X || 8 X X | 3 5 X | 2 X X || x(x*x-6x-9)-x(x*x-8x-15)+2x(3-x) 填九宫格帮帮忙.x x 6 x x 7 x x 98 x x x 3 x 1 x x 9 x x 6 x 5 x 3 x x x 3 x x x x 1 8x x x 9 x 1 x x x2 1 x x x x 6 x x x 6 x 7 x 3 x x 1 x x 9 x 2 x x x 47 x x 8 x x 5 x x X+0.5X=3 X-0.8X=8 x-2=(104-x)+2 6x-59=10x-75 (x+10)+(x-15)=280-x4（x-62)=x-38 60x-40=(60+20)*(x-5) 32x+32*0.5-25x+64x=24x+496-49x x+15=3*(109-x ) 5(3x-1.4)=2(6x-0.5) 3(x+0.9)=5(x-1.7) 13x-4(2x+5)=17(x-2)-4(2x-1) (13x+8)/3=5x-1x-60=2[(3561-x)+100]+1 (x+9)+12=2[(x-9)-1 80+x=(56-x)*3 x=x (x+3)(x-4)(x+5)(x-6)+80因式分解 (x-3)(x+4)(x-5)(x+6)+80因式分解 (x+3)(x-4)(x+5)(x-6)+80因式分解, x-3(20-x)=3x-7(9-x) 4x-3x(20-x)=4求x