Step 1. Subtract 3 from both sides
2|7x - 4| = 51 - 3
Step 2. Simplify 51 - 3 to 48
2|7x - 4| = 48
Step 3. Divide both sides by 2
|7x - 4| = 48/2
Step 4. Simplify 48/2 to 24
|7x - 4| = 24
Step 5 Break down the problem into these 2 equations
7x - 4 = 24
-(7x - 4) = 24
Step 6. Solve the 1st equation: 7x - 4 = 24
x = 4
Step 7. Solve the 2nd equation: -(7x - 4) = 24
x = -20/7
Step 8. Collect all solutions
x = -20/7,4
The answer is C.
