Update app.py

app.py

@@ -13,7 +13,8 @@ def parse_equation(equation):
     parts = equation.split('=')
     coef = parts[0].split('x')
     a = float(coef[0]) if coef[0] else 1
-    b = float(coef[1].replace('y', '').replace('+', '').replace('-', '').strip()) if 'y' in coef[1] else 0
+    b_str = coef[1].replace('y', '').replace('+', '').replace('-', '').strip()
+    b = float(b_str) if b_str else 0
     c = float(parts[1])
     return a, b, c