Tìm x, biết

tim x
2x+3x=5x-2x
7x+8x=10
54+46=2x
87x-4x=0
(2x-3+8)+(5x-7+9)=19
tinh
36+72-9=?
61-920-(-40)=?
tim x
2x+45=0
3x+46=0
4x+47=0
710+2x=0
512=(72x+x)+(55-x)
7x-2=(5x-7)+(6x-3)
7x+2x^2=0
75-8x=6x
52x-4x=66
4x-72+10=x+x-4x