diff --git a/lib/node/Term.js b/lib/node/Term.js
index 34bb04ae..21f5694b 100644
--- a/lib/node/Term.js
+++ b/lib/node/Term.js
@@ -114,7 +114,7 @@ Term.parseNode = function(node, baseNodeFunc, onlyImplicitMultiplication) {
         throw Error('Expected two arguments to *');
       }
       const coeffNode = node.args[0];
-      if (!NodeType.isConstantOrConstantFraction(coeffNode)) {
+      if (!NodeType.isConstantOrConstantFraction(coeffNode, true)) {
         throw Error('Expected coefficient to be constant or fraction of ' +
           'constants term, got ' + coeffNode);
       }
diff --git a/lib/node/Type.js b/lib/node/Type.js
index c1d6bd96..c3cdeaa1 100644
--- a/lib/node/Type.js
+++ b/lib/node/Type.js
@@ -78,6 +78,16 @@ NodeType.isConstantOrConstantFraction = function(node, allowUnaryMinus=false) {
   }
 };
 
+NodeType.isOverallConstant = function (node) {
+  if (NodeType.isConstantOrConstantFraction(node, true)) {
+    return true
+  } else if (NodeType.isUnaryMinus(node)) {
+    return NodeType.isOverallConstant(node.args[0])
+  } else if (NodeType.isParenthesis(node)) {
+    return NodeType.isOverallConstant(node.content)
+  }
+}
+
 NodeType.isIntegerFraction = function(node, allowUnaryMinus=false) {
   if (!NodeType.isConstantFraction(node, allowUnaryMinus)) {
     return false;
diff --git a/lib/solveEquation/stepThrough.js b/lib/solveEquation/stepThrough.js
index 40c1474c..744db20e 100644
--- a/lib/solveEquation/stepThrough.js
+++ b/lib/solveEquation/stepThrough.js
@@ -257,11 +257,10 @@ function solveConstantEquation(equation, debug, steps=[]) {
 
   // If the left or right side didn't have any steps, unnecessary parens
   // might not have been removed, so do that now.
-  equation.leftNode = removeUnnecessaryParens(equation.leftNode);
-  equation.rightNode = removeUnnecessaryParens(equation.rightNode);
+  equation.leftNode = removeUnnecessaryParens(equation.leftNode, true);
+  equation.rightNode = removeUnnecessaryParens(equation.rightNode, true);
 
-  if (!Node.Type.isConstantOrConstantFraction(equation.leftNode, true) ||
-      !Node.Type.isConstantOrConstantFraction(equation.rightNode, true)) {
+  if (!Node.Type.isOverallConstant(equation.leftNode) || !Node.Type.isOverallConstant(equation.rightNode)) {
     throw Error('Expected both nodes to be constants, instead got: ' +
                 equation.ascii());
   }
diff --git a/lib/util/flattenOperands.js b/lib/util/flattenOperands.js
index 8e5c0343..8aa63d1a 100644
--- a/lib/util/flattenOperands.js
+++ b/lib/util/flattenOperands.js
@@ -86,7 +86,9 @@ function flattenOperands(node) {
     return node;
   }
   else if (Node.Type.isUnaryMinus(node)) {
-    const arg = flattenOperands(node.args[0]);
+    // since arg is changed when it is negated, clone it before negation to avoid
+    // modifiying original reference
+    const arg = flattenOperands(node.args[0].cloneDeep());
     const flattenedNode = Negative.negate(arg, true);
     if (node.changeGroup) {
       flattenedNode.changeGroup = node.changeGroup;
diff --git a/lib/util/removeUnnecessaryParens.js b/lib/util/removeUnnecessaryParens.js
index 3bbf796d..3d3c1447 100644
--- a/lib/util/removeUnnecessaryParens.js
+++ b/lib/util/removeUnnecessaryParens.js
@@ -37,8 +37,7 @@ function removeUnnecessaryParensSearch(node) {
     return node;
   }
   else if (Node.Type.isUnaryMinus(node)) {
-    const content = node.args[0];
-    node.args[0] = removeUnnecessaryParensSearch(content);
+    node.args[0] = removeUnnecessaryParensSearch(node.args[0])
     return node;
   }
   else {
diff --git a/test/solveEquation/solveEquation.test.js b/test/solveEquation/solveEquation.test.js
index 251179fe..2d0eb4c0 100644
--- a/test/solveEquation/solveEquation.test.js
+++ b/test/solveEquation/solveEquation.test.js
@@ -99,7 +99,9 @@ describe('solveEquation for =', function () {
     ['((x)/(4))=4', 'x = 16'],
     ['(2x-12)=(x+4)', 'x = 16'],
     ['x+y=x+y', '0 = 0'],
-    ['y + 2x = 14 + y', 'x = 7']
+    ['y + 2x = 14 + y', 'x = 7'],
+    ['-(x/2) = 4', 'x = -8'],
+    ['-((1)/(3)) = ((-1)/(3))', '-(1/3) = -1/3']
     // TODO: fix these cases, fail because lack of factoring support, for complex #s,
     // for taking the sqrt of both sides, etc
     // ['(x + y) (y + 2) = 0', 'y = -y'],
diff --git a/test/util/removeUnnecessaryParens.test.js b/test/util/removeUnnecessaryParens.test.js
index 9d7520ab..72f772a1 100644
--- a/test/util/removeUnnecessaryParens.test.js
+++ b/test/util/removeUnnecessaryParens.test.js
@@ -17,6 +17,7 @@ describe('removeUnnecessaryParens', function () {
     ['x + (12)', 'x + 12'],
     ['x + (y)', 'x + y'],
     ['x + -(y)', 'x - y'],
+    ['((((1))))', '1'],
     ['((3 - 5)) * x', '(3 - 5) * x'],
     ['((3 - 5)) * x', '(3 - 5) * x'],
     ['(((-5)))', '-5'],