123456789 number position does not move. With the addition and subtraction method plus brackets, finally equal to 2

123456789 number position does not move. With the addition and subtraction method plus brackets, finally equal to 2

-1+2+3-4+5+6-7-8+9 =5
1+2+3+4-5+6-7+8-9 =3
1-2+3-4+5+6-7+8-9 =1
It can't be equal to two in the end

12 * 46 (), () 64 * 21, fill in the appropriate number in the brackets to make the two expressions equal
1. Let this number be X. how can we transform 46 (x) and (x) 64 into algebraic expressions about x
2. The list is represented by an algebraic expression for X

46(x)=46*10+x
(x)64=100*x+64
12(46*10+x)=(100*x+64)*21
x=2

12×46□=□64×21
Please

462
two hundred and sixty-four