!set n=$counter

question$n=!record 30 of lang/remarks.$taal
#@ Los de volgende vergelijking op <br>(Bereken dus de waarde van de letter)
!if $subject=27
    steps=0
    breuken=0
    variabelen=0
!endif
!if $steps=1
    math=0
    checkfile=exos/checkfile4.proc
    tekst=!record 31 of lang/remarks.$taal
    #@En laat ook een paar tussenstappen zien...
    question$n=$(question$n)<br>$tekst
    var4=2
    var5=7
!else
    var4=1
    var5=1
    math=1
    checkfile=exos/checkfile1.proc
!endif


!if $level =0
    R=$counter
!else
    R=$level
!endif    

!if $variabelen=1
    var1=!randitem a,b,c,d,f,x,y,z,p,g,k,t,r,n,m
!else
    var1=x
!endif
varlist=$var1
mathviewpanel=$module_title:->:/:*:-:+
!if $breuken=0
    a=!randitem 2,3,4,5,6,7,8,9,10,11,12,13,14
    answer$n=!randitem 2,3,4,5,6,7,8,9,10,11,12,13,14
    d=!randitem 1,2,3,4,5,6,7
    !if $R=1 
	# e+x=a*x+d => b+x=a*x => b=(a-1)x	
	b=$[($a-1)*$(answer$n)]
	e=$[$b+$d]	    
	formula$n=$e + $var1 \,\,\,=\,\,\,$a \cdot $var1 + $d
	texanswer$n=$e - $d + $var1 \,\,=\,\,$a \cdot $var1 \Longrightarrow $b\,\,\,=\,\,$a \cdot $var1 - $var1 \Longrightarrow $b\,\,=$[$a-1]\cdot $var1 \Longrightarrow $var1 \,\,=\frac{$b}{$[$a-1]} = $(answer$n)
     !exit
    !endif
	
    !if $R=2 
	# e-x=a*x+d => b-x=a*x => b=(a+1)x
	b=$[($a+1)*$(answer$n)]
	e=$[$b+$d]
	formula$n=$e - $var1 \,\,\,=\,\,\,$a \cdot $var1 + $d
	texanswer$n=$e - $d  - $var1 \,\,\,=\,\,\,$a \cdot $var1 \Longrightarrow $b \,=\,\,\,$a \cdot $var1 + $var1 \Longrightarrow $b \,\,=\,\,$[$a+1]\cdot $var1 \Longrightarrow $var1 \,\,=\frac{$b}{$[$a+1]} = $(answer$n)
     !exit
    !endif

    !if $R=3
	pm=!randitem -,+
	!if $pm=+
	    mp=-
	!else
	    mp=+
	!endif 
	# e-cx=a*x+d => b-cx=a*x => b=(a+c)x
	c=!randitem 2,3,4,5,6,7,8
	b=$[($a+$c)*$(answer$n)]
	e=$[$b $pm $d]
	formula$n=$e - $c\cdot $var1 \,\,\,=\,\,\,$a \cdot $var1 $pm $d
	texanswer$n=$e $mp $d  - $c\cdot $var1 \,\,\,=\,\,\,$a \cdot $var1 \Longrightarrow $b \,=\,\,\,$a \cdot $var1 + $c\cdot $var1 \Longrightarrow $b \,\,=\,\,$[$a+$c]\cdot $var1 \Longrightarrow $var1 \,\,=\frac{$b}{$[$a+$c]} = $(answer$n)
     !exit
    !endif
    
    !if $R=4 
	# e+cx=a*x+d => b+cx=a*x => b=(a-c)x
	c=!randitem 2,3,4,5,6,7,8
	b=$[($a-$c)*$(answer$n)]
	e=$[$b+$d]
	formula$n=$e + $c\cdot $var1 \,\,\,=\,\,\,$a \cdot $var1 + $d
	texanswer$n=$e - $d  + $c\cdot $var1 \,\,\,=\,\,\,$a \cdot $var1 \Longrightarrow $b \,=\,\,\,$a \cdot $var1 - $c\cdot $var1 \Longrightarrow $b \,\,=\,\,$[$a-$c]\cdot $var1 \Longrightarrow $var1 \,\,=\frac{$b}{$[$a-$c]} = $(answer$n)
     !exit
    !endif
		
    !if $R>4
	# e-cx=a*x+d => b-cx=a*x => b=(a+c)x
	c=!randitem 2,3,4,5,6,7,8
	b=$[($a+$c)*$(answer$n)]
	e=$[$b-$d]
	formula$n=$e - $c\cdot $var1 \,\,\,=\,\,\,$a \cdot $var1 - $d
	texanswer$n=$e + $d  - $c\cdot $var1 \,\,\,=\,\,\,$a \cdot $var1 \Longrightarrow $b \,=\,\,\,$a \cdot $var1 + $c\cdot $var1 \Longrightarrow $b \,\,=\,\,$[$a+$c]\cdot $var1 \Longrightarrow $var1 \,\,=\frac{$b}{$[$a+$c]} = $(answer$n)
     !exit
    !endif
    
!else
    a=!randitem 1/3,1/4,1/5,1/7,1/8,1/9,1/10,2/3,2/5,3/5,2/7,3/7,4/7,5/7,5/8,3/8,4/9
    aa=!replace internal / by , in $a
    a1=!item 1 of $aa
    a2=!item 2 of $aa
    b1=$[$a1+1]
    A=\frac{$a1}{$a2}
    b=!randitem 2,3,4,5,6,7,8,9,10,11,12,13,14
    d=!randitem 1,2,3,4,5,6
    e=$[$b+$d]
    !if $R=1
        B=\frac{$b1}{$a2}
	#e-x=a*x+d =>b*x=x + a => x=a/(b-1)
	gg=!exec pari B=$a/($b-1)\
	printtex(B)
	answer$n=!line 1 of $gg
	G=!line 2 of $gg	    
	formula$n=$b\cdot $var1 + $A\,\,\,=\,\,\,$var1 + $B
	texanswer$n=$[$b-1]\cdot $var1 = $A \Longrightarrow $var1= \frac{1}{$[$b-1]} \cdot \frac{$a1}{$a2} = $G 
     !exit
    !endif
    
    !if $R=2 
	#e-x=a*x+d =>b+x=a*x =>x=b/(a-1)	
	gg=!exec pari A=$b/($a-1)\
	printtex(A)
	answer$n=!line 1 of $gg
	G=!line 2 of $gg	    
	formula$n=$e + $var1 \,\,\,=\,\,\,$A \cdot $var1 + $d
	texanswer$n=$b + $var1 \,\,=\,\,$A \cdot $var1 \Longrightarrow $b\,\,\,=\,\,$A \cdot $var1 - $var1 \Longrightarrow $b\,\,=\frac{$[$a1-$a2]}{$a2} \cdot $var1 \Longrightarrow $var1=$b\cdot \frac{$a2}{$[$a1-$a2]} = $G
	#a-1 =(a1-a2)/a2
     !exit	
    !endif
	
    !if $R=3 
	#e-x=a*x+d => b-x=a*x =>b=(a+1)x
	gg=!exec pari A=$b/($a+1)\
	printtex(A)
	answer$n=!line 1 of $gg
	G=!line 2 of $gg	    
	formula$n=$e - $var1 \,\,\,=\,\,\,$A \cdot $var1 + $d
	texanswer$n=$b - $var1 \,\,\,=\,\,\,$A \cdot $var1 \Longrightarrow $b\,\,\,=\,\,$A \cdot $var1 + $var1 \Longrightarrow $b\,\,=\frac{$[$a1+$a2]}{$a2}\cdot $var1 \Longrightarrow $var1=$b\cdot \frac{$a2}{$[$a1+$a2]} = $G
     !exit
    !endif
	
    !if $R>3
	!if $R=4 
	    #a*x=x - b => x=-b/(a-1)
	    gg=!exec pari C=-1*$b/($a-1)\
	    printtex(C)
	    answer$n=!line 1 of $gg
	    G=!line 2 of $gg	    
	    formula$n=$A \cdot $var1 - $d\,\,\,=\,\,\,$var1 - $e 
	    texanswer$n=$A \cdot $var1 \,\,=\,\, $var1 -$b \Longrightarrow $A \cdot $var1 - $var1 = - $b \Longrightarrow \frac{$[$a1 - $a2]}{$a2} \cdot $var1 = -$b \Longrightarrow $var1=\frac{$a2}{$[$a1 - $a2]} \cdot - $b   = $G 
        !exit
    !else	
	#b*x=x + a => b= (x+a)/x
	answer$n=!randitem 2,3,4,5,6,7,8,9,10,11,12,13,14
	a=!randitem 2,3,4,5,6,7,8,9,10,11,12,13,14
	c=!randitem 1,2,3,4
	d=$[$a+$c]
	bb=!exec pari A=($(answer$n)+$a)/$(answer$n)\
	printtex(A)
	b=!line 1 of $bb
	B=!line 2 of $bb
	formula$n=$c + $var1 \cdot $B \,\,\,=\,\,\,$var1 + $d
	texanswer$n=$var1\cdot $B - $var1 = $a \Longrightarrow $var1 \,\,=\,\,\frac{$a}{$B - 1} =  $(answer$n) 
     !exit
    !endif
!endif
