Ella simplifies (3 b + 4 r) + (negative 2 b minus r) and says the result is b Plus 5r. What error did Ella make? Ella incorrectly combined the b coefficients. The correctly simplified expression is 5 b + 5 r. Ella incorrectly combined the b coefficients. The correctly simplified expression is Negative b + 5 r. Ella incorrectly combined the r coefficients. The correctly simplified expression is b – 5r. Ella incorrectly combined the r coefficients. The correctly simplified expression is b Plus 3r.