checkfile=exos/checkfile8.proc
image=0
questiontype=0
math=0
!set n=$counter

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

!if $variabelen=1
    letters=a,b,c,d,f,x,y,z,p,g,k,t,r,n,m
    letters=!shuffle $letters 
    var1=!item 1 of $letters
    var2=!item 2 of $letters
    var3=!item 3 of $letters
!else
    var1=x
    var2=y
    var3=u
!endif
var4=#
## trick to use 1 checkfile 
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 +,-
exotitle=!record 65 of lang/remarks.$taal
#@ Schrijf het volgende stelsel van twee vergelijking op als &eacute;&eacute;n vergelijking <br>Schrijf <em>$var2</em> als functie van  <em>$var1</em> .
question$n=!record 66 of lang/remarks.$taal
#@ Schrijf de twee vergelijkingen als &eacute;&eacute;n formule <br><em>Dus schrijf <tt>$var2</tt> als functie van  <tt>$var1</tt> 
!if $R=1
    # x=z pm b => z=(x - (pm b))
    # y=z mp  c
    # texanswer$n= y=(x - (pm b)) pm c
    g=!exec pari A=($var1 - ($pm $b)) $mp $c\
    printtex(A)
    g1=!line 1 of $g
    g2=!line 2 of $g
    texanswer$n=$var2 \,=\, $g2
    answer$n=$g1
    formula$n=\left\{ \begin{array}{l} $var1 = $var3 $pm $b  \\ \\ $var2 = $var3 $mp $c \end{array}\right.
 !exit
!endif
	
!if $R=2
    # x=az => z=x/a
    # y=dz mp  c
    # texanswer$n= y=dx/a mp c 
    g=!exec pari A=$d*$var1/$a $mp $c\
    printtex(A)
    g1=!line 1 of $g
    g2=!line 2 of $g    
    texanswer$n=$var2 \,=\, $g2
    answer$n=$g1
    formula$n=\left\{ \begin{array}{l} $var1 = $a \cdot $var3 \\ \\ $var2 = $d \cdot $var3 $mp $c \end{array}\right.
 !exit
!endif
	
!if $R=3
    # x=az pm b => z= (x - (pm b))/a
    # y=dz mp  c
    # texanswer$n= y=d((x - (pm b))/a ) mp c 
    g=!exec pari A=$d*(($var1- ($pm $b) )/$a ) $mp $c\
    printtex(A)
    g1=!line 1 of $g
    g2=!line 2 of $g
    texanswer$n=$var2 \,=\, $g2
    answer$n=$g1
    formula$n=\left\{ \begin{array}{l} $var1 = $a \cdot $var3 $pm $b \\ \\ $var2 = $d \cdot $var3 $mp $c \end{array}\right.
  !exit
!endif
!if $R>3
    mytexsize=+2
    keuze=!randitem 1,2
    !if $keuze=1	
	# x=z/a pm b => z/a = x-(pm b) => z=a*(x-(pm b))
	# y=dz mp  c
        # texanswer$n= y=d*(a*(x-(pm b))) mp c
        g=!exec pari A=$d*($a*($var1-($pm $b))) $mp $c\
        printtex(A)
        g1=!line 1 of $g
        g2=!line 2 of $g
        texanswer$n=$var2 \,=\, $g2
        answer$n=$g1
        formula$n=\left\{ \begin{array}{l} $var3 = \frac{1}{$a} \cdot $var1 $pm $b \\ \\ $var2 = $d \cdot $var3 $mp $c \end{array}\right.
     !exit
    !else
	e=!randitem 2,3,4,5,6,7,8
	a=$[$a+$e]
	# x=e*z/a pm b => ex/a=x- (pm b) => ex=a(x- (pm b)) => x=a(x- (pm b))/e
	# y=dz mp  c
	# texanswer$n= y=d*(a(x- (pm b))/e ) mp c 
	g=!exec pari A=$d*($a*($var1-($pm $b))/$e ) $mp $c\
	printtex(A)
	g1=!line 1 of $g
	g2=!line 2 of $g
	texanswer$n=$var2 \,=\, $g2
	answer$n=$g1
	formula$n=\left\{ \begin{array}{l} $var3 = \frac{$e}{$a} \cdot $var1 $pm $b \\ \\ $var2 = $d \cdot $var3 $mp $c \end{array}\right.
     !exit
    !endif	
!endif
