x:18=0.5, x=0.5×18, x=9; | 1.8:x= x=1.8÷, x=5.4; | x:20=4:5 5x=20×4 5x÷5=80÷5 x=16; |
= 7x=3×8, 7x÷7=24÷7, x= | x+x= (+)x= x÷=÷ x= | 1x-20=29 1x-20+20=29+20 1x÷=49÷ x=28 |
x÷= x÷×=× x= x÷=÷, x= | 4x+5x= 9x= 9x÷9=÷9 x= | x+x= 1x÷=÷ x=× x= |
x+20=50 x+20-20=50-20 x÷=30÷ x=40 | x-x= (1-)x=, x÷=÷ x= | x-= x-+=+ x÷=÷ x= |