@center@ = @lib.check_number(diff,30)@ @lib.check_string(sign[1],15)@ @lib.check_number(term[1],30)@ = @lib.check_number(value[1],30)@ 

@vspace@
@center@ x - (y - @term[2]@) = @lib.check_number(diff,30)@ @lib.check_string(sign[1],15)@ @lib.check_number(term[2],30)@ = @lib.check_number(value[2],30)@ 

@vspace@
@center@ (x - @term[3]@) - y  = @lib.check_number(diff,30)@ @lib.check_string(sign[2],15)@ @lib.check_number(term[3],30)@ = @lib.check_number(value[3],30)@ 

@vspace@
@center@ x - (y + @term[4]@) = @lib.check_number(diff,30)@ @lib.check_string(sign[2],15)@ @lib.check_number(term[4],30)@ = @lib.check_number(value[4],30)@ 
 
@vspace@
         
         