Problem #PRU-79636

Problem

Izzy wrote a correct equality on the board: $35+10-41=42+12-50$, and then subtracted 4 from both parts: $35+10-45=42+12-54$. She noticed that on the left hand side of the equation all of the numbers are divisible by 5, and on the right hand side by 6. Then she took 5 outside of the brackets on the left hand side and 6 on the right hand side and got $5(7+2-9)4=6(7+2-9)$. Having simplified both sides by a common multiplier, Izzy found that $5=6$. Where did she go wrong?