42:=x:
80÷x=20 12x+8x-12=28(2x-1)+10=37 1.6x+3.4x-x-5=27(3x+5)÷2=(5x-9)÷3 x-21×=4 x÷=÷
3x+7x+10=90 3(x-12)+23=357x-8=2x+27 5x-18=3–2x
x+4=10 x-12=34 8x=964x-30=0 8.3x-2x=63 x÷10=5.2
(x- 4.5)=7 x-25%x=10
3x=5(32-x) 0.36×5-x=