Calculate: (a+10 b-9)+(3 a-5 b+4 c)+(2 c+b-6)

Expression: $$( a + 10 b - 9 ) + ( 3 a - 5 b + 4 c ) + ( 2 c + b - 6 )$$

Combine $a$ and $3a$ to get $4a$.

$$4a+10b-9-5b+4c+2c+b-6$$

Combine $10b$ and $-5b$ to get $5b$.

$$4a+5b-9+4c+2c+b-6$$

Combine $4c$ and $2c$ to get $6c$.

$$4a+5b-9+6c+b-6$$

Combine $5b$ and $b$ to get $6b$.

$$4a+6b-9+6c-6$$

Subtract $6$ from $-9$ to get $-15$.

$$4a+6b-15+6c$$