7x-4 (6-x) + 12. if x=6

We just need to substitute in 6 whether we see an x:

(7*6) - 4 * (6-6) + 12

= 42 - 4*0 + 12

=54

7x-4 (6-x) + 12

Substitute 6 for x.

7 (6) - 4 (6 - 6) + 12

Use distributive property (Multiply - 4 by 6 and - 6)

7 (6) - 24 - 24 + 12

Multiply 7 by 6

42 - 24 - 24 + 12

Subtract 24 from 42

18 - 24 + 12

Subtract 24 from 18

-6 + 12

Add

Final Answer: 6