9-21=3(t-7)+6t

Solution for 9-21=3(t-7)+6t equation:

9-21=3(t-7)+6t

We move all terms to the left:

9-21-(3(t-7)+6t)=0

We add all the numbers together, and all the variables

-(3(t-7)+6t)-12=0


We calculate terms in parentheses: -(3(t-7)+6t), so:

3(t-7)+6t

We add all the numbers together, and all the variables

6t+3(t-7)

We multiply parentheses

6t+3t-21

We add all the numbers together, and all the variables

9t-21

Back to the equation:

-(9t-21)


We get rid of parentheses

-9t+21-12=0

We add all the numbers together, and all the variables

-9t+9=0

We move all terms containing t to the left, all other terms to the right

-9t=-9

t=-9/-9

t=1