下列方程用等式的性质如何解?

显示全部楼层 · 2009-2-21 13:58:24

(1) X - 5 = 6
[X减五等于六]
(2) 0.3X = 45
[零点三X等于四十五]
(3) 2 - 1/4X =3[二减四分之一X等于三]
(4) 5X + 4 = 0 [五X加四等于零]

千问 · 2009-2-21 13:58:24

(1) X - 5 = 6两边同时加上5X-5+5=6+5X=11(2) 0.3X = 45两边同时除以0.30.3X÷0.3=45÷0.3X=150(3) 2 - 1/4X =3两边同时减去0.32-1/4X-2=3-2-1/4X=1两边同时乘以-4(-4)*(-1/4X)=1*(-4)X=-4(4) 5X + 4 = 0两边同时减去45X+4-4=0-45X=-4两边同时除以55X÷5=-4÷5X=-4/5...