bewerking=nivo/bewerking9.proc
!set n=$teller
PLAATJE=0
!if $graad =0
    R=$teller
!else
    R=$graad
!endif        

!if $variabelen=1
    letters=a,b,c,d,f,x,y,z,p,g,k,t,r,n,m
    letters=!shuffle $letters 
    X$n=!item 1 of $letters
    Y$n=!item 2 of $letters
    Z$n=!item 3 of $letters
    K$n=!item 4 of $letters
!else
    X$n=x
    Y$n=y
    Z$n=u
    K$n=v
!endif   
getallen=!shuffle 2,3,4,5,6,7,8,9,10
a=!item 1 of $getallen
b=!item 2 of $getallen
c=!item 3 of $getallen
d=!item 4 of $getallen
e=!item 5 of $getallen
f=!item 6 of $getallen
g=!item 7 of $getallen
h=!item 8 of $getallen     	
pm=!randitem +,-
mp=!randitem +,-
mm=!randitem +,-
    
#nivo_title=Schrijf het volgende stelsel van drie vergelijking op als &eacute;&eacute;n vergelijking 
#somtekst$n=Schrijf de drie vergelijkingen als &eacute;&eacute;n formule <br><em>Dus geef <tt>$(Y$n)</tt> als functie van <tt>$(X$n)</tt></em> .
    
nivo_title=!record 25 of lang/remarks.$taal
somtekst$n=!record 67 of lang/remarks.$taal
!if $R=1
    # k=x mm d
    # z=k pm b
    # y=z mp  c
    # goed$n= y= ((x mm d) pm b) mp c 
    g=!exec pari A= (($(X$n) $mm $d) $pm $b) $mp $c
    printtex(A)
    g1=!line 1 of $g
    g2=!line 2 of $g
    goed$n=$(Y$n) \,=\, $g2
    GOED$n=$g1
    som$n=\left\{ \begin{array}{l}$(K$n)=$(X$n) $mm $d \\ $(Z$n) = $(K$n) $pm $b \\ $(Y$n) = $(Z$n) $mp $c \end{array}\right.
    extra$n=$empty
 !exit
!endif
	
!if $R=2
    # k=x mm d
    # z=ak
    # y=dz mp  c
    # goed$n= y= d( a*(x mm d)) pm c 
    g=!exec pari A=$d*($a*($(X$n) $mm $d)) $mp $c\
    printtex(A)
    g1=!line 1 of $g
    g2=!line 2 of $g    
    goed$n=$(Y$n) \,=\, $g2
    GOED$n=$g1
    som$n=\left\{ \begin{array}{l}$(K$n)=$(X$n) $mm $d \\  $(Z$n) = $a \cdot $(K$n) \\ $(Y$n) = $d \cdot $(Z$n) $mp $c \end{array}\right.
    extra$n=$empty
 !exit
!endif
	
!if $R=3
    # k=x mm e
    # z=ak pm b
    # y=dz mp  c
    # goed$n= y= d*(a*(x mm e) pm b ) mp c 
    g=!exec pari A=$d*($a*($(X$n) $mm $e) $pm $b) $mp $c\
    printtex(A)
    g1=!line 1 of $g
    g2=!line 2 of $g
    goed$n=$(Y$n) \,=\, $g2
    GOED$n=$g1
    som$n=\left\{ \begin{array}{l} $(K$n) = $(X$n) $mm $e \\ $(Z$n) = $a \cdot $(K$n) $pm $b \\  $(Y$n) = $d \cdot $(Z$n) $mp $c \end{array}\right.
    extra$n=$empty
  !exit
!endif
!if $R>3
    wims_texsize=+2
    keuze=!randitem 1,2
    !if $keuze=1
	# k=x mm e	
	# z=k/a pm b
	# y=dz mp  c
        # goed$n= y=d((x mm e)/a $pm b) mp c 
        g=!exec pari A=$d*(($(X$n) $mm $e)/$a $pm $b) $mp $c\
        printtex(A)
        g1=!line 1 of $g
        g2=!line 2 of $g
        goed$n=$(Y$n) \,=\, $g2
        GOED$n=$g1
        som$n=\left\{ \begin{array}{l}$(K$n) = $(X$n) $mm $e \\  $(Z$n) = \frac{1}{$a} \cdot $(K$n) $pm $b \\ $(Y$n) = $d \cdot $(Z$n) $mp $c \end{array}\right.
        extra$n=$empty
     !exit
    !else
	# k=x mm f
	# z=e*k/a pm b
	# y=dz mp  c
	# goed$n= y= d(e*(x mm f)/a pm b) mp c
	g=!exec pari A=$d*($e*($(X$n) $mm $f)/$a $pm $b) $mp $c\
	printtex(A)
	g1=!line 1 of $g
	g2=!line 2 of $g
	goed$n=$(Y$n) \,=\, $g2
	GOED$n=$g1
	som$n=\left\{ \begin{array}{l}$(K$n)= $(X$n) $mm $f \\  $(Z$n) = \frac{$e}{$a} \cdot $(K$n) $pm $b  \\ $(Y$n) = $d \cdot $(Z$n) $mp $c \end{array}\right.
	extra$n=$empty
     !exit
    !endif	
!endif