The answer is: [C]: x < 7 .
Explanation:
Given:
12x – 3x + 11 > 4x – (17 – 9x) ;
We need to simplify EACH side of the inequality; and then rewrite:
Let us start with the "left-hand side" :
12x – 3x + 11
We see that among the three terms, there are 2 (two) "like terms";
"12x" and "-3x" ;
So, 12x – 3x = 9x ; and bring down the remaining term, " +11" ;
9x + 11 ;
Now, let us simplify the 'right-hand side' of the inequality:
4x – (17 – 9x) ;
Treat this expression as:
4x – 1(17 – 9x) ;
(Note: The coefficient "1" is implied; since anything multiplied by "1" is that same value").
Note the "distributive property of multiplication" :
a* (b + c) = ab + ac ; AND:
a* (b – c) = ab – ac ;
So, we have the expression:
4x – 1(17 – 9x) ;
Take the: -1*(17 – 9x); and simplify;
-1*(17 – 9x) = (-1 * 17) – (-1 * 9x) = -17 – (-9x) = -17 + 9x ;
We have:
-17 + 9x ; Rewrite as: 9x – 17
Now, bring down the "4x"; and rewrite the expression:
9x – 17 + 4x ;
Notice that there are 2 (two) "like terms" out of the 3 (three) terms in this expression:
+9x and +4x ;
Combine these like terms; and simplify:
4x + 9x = 13x ;
Now, bring down the "– 17 " ; and rewrite the entire "right-hand side" expression:
13x – 17 ;
Now, we can rewrite the entire equality, by substituting our simplified expressions:
9x + 11 > 13x – 17 ; Now, solve for "x" ;
Subtract "9x" from EACH side; and add "17" to EACH side;
9x + 11 – 9x + 17 > 13x – 17 – 9x + 17 ;
28 > 4x ;
Now, divide EACH side of the inequality by "4", to isolate "x" on one side of the inequality; and to solve for "x" ;
28 / 4 > 4x / 4 ;
7 > x ; or, write as: x < 7 ; which is: "Answer choice: [C] ".