1×(x+4)+4×( 1+x)- 1×4 = 49(x- 13)÷(80-x- 13)= 5

2.8x = 19.32–6.4x(x- 1)×22 =(x-3)×26

( 1.6x-3-x)×2.5 = 30×2 ^ 3( 105+x)= 10x+ 1

0.4(x-0.2)+ 1.5 = 0.7x-0.38 x- 10 =〔2(x- 10)-5〕×5

x-30×3 = 490-x-20×2 8×(x+5)=(8-3)x×2

2.6x- 1.4x = 2.6(650-x)+ 1.4(650-x)5〔 104-x-(x-40)〕= 4(x-40)-30

35(x-2)- 15(5x-6)=(22x-63)-2 1(3x-4)

(6x+ 180)/(5x+30)= 1.5