Step 1 :Isolate a square root on the left hand side : Original equation 
 4 = √-6-2x+√31-3x
 Isolate
 -√-6-2x = -4+√31-3x
 Tidy up 
 √-6-2x = 4-√31-3x
Step 2 :Eliminate the radical on the left hand side : Raise both sides to the second power
 (√-6-2x)2 = (4-√31-3x)2
 After squaring 
 -6-2x = 31-3x+16-8√31-3x
Step 3 :Get remaining radical by itself : Current equation 
 -6-2x = 31-3x+16-8√31-3x
 Isolate radical on the left hand side
 8√31-3x = 6+2x+31-3x+16
 Tidy up 
 8√31-3x = 53-x
Step 4 :Eliminate the radical on the left hand side : Raise both sides to the second power
 (8√31-3x)2 = (53-x)2
 After squaring 
 1984-192x = x2-106x+2809
Step 5 :Solve the quadratic equation : Rearranged equation
 x2 + 86x + 825 = 0
 This equation has two rational roots:
  {x1, x2}={-11, -75}
 Step 6 :Check that the first solution is correct : Original equation, root isolated, after tidy up
 √-6-2x = 4-√31-3x
 Plug in -11 for x 
 √-6-2•(-11) = 4-√31-3•(-11)
 Simplify
  √16 = -4
  Solution does not check 
 4 ≠ -4 
Step 7 :Check that the second solution is correct : Original equation, root isolated, after tidy up
 √-6-2x = 4-√31-3x
 Plug in -75 for x 
 √-6-2•(-75) = 4-√31-3•(-75)
 Simplify
  √144 = -12
  Solution does not check 
  12 ≠ -12 Hopefully this helped You