Use Compute not Formula in answer

Author: gajennings

OpenProblemLibrary/PCC/BasicAlgebra/SlopeAndY-InterceptCalculations/WriteEquationByGraph60.pg

@@ -56,7 +56,7 @@ $pt2=Compute("($x2,$y2)");
 Context("Numeric");
 Context()->noreduce('(-x)-y','(-x)+y');
 parser::Assignment->Allow;
-$ansSI=Formula("x=$a")->reduce;
+$ansSI=Compute("x=$a")->reduce;
 
 $xmin = -5;
 $xmax = -$xmin;
@@ -120,7 +120,7 @@ Context()->normalStrings;
 
 ##############################################
 
-ANS(Compute($ansSI)->cmp());
+ANS($ansSI->cmp());
 
 $grCorrect = init_graph($xmin,$ymin,$xmax,$ymax,
 axes=>[0,0],