X-X=400 X-0.125X=8 =

X+X=18 X×( + )= x－0.375x=

x×+=4× X－X＝12　　 　　5 X－2.4×5＝8

0.36×5- x = (x- 4.5) = 7 x- 25%x = 10

x- 0.8x = 16+6 20 x- 8.5= 1.5 x- x -4= 21

X＋25%X=90 X－X=

一、解方程：＋－×÷＝

(1) 3.5X＋1.8＝12.3 (5) X＋X＝21 (6) X＋X＝

(7) 3.6X÷2＝2.16 (8) X＋X＝ (2) 0.8X－4＝1.6

(3) 5X÷2＝10 (4) X－0.25X＝3 (9) X－X＝

(10) X－＝ (11) 2X＋7X＝ (12) ＋X＝