Number 15 is no solution.
Number 27 is that x has to be between -2 or 2.
This could be explained as -2≤x≤2
Answer:
X=8
Step-by-step explanation:
17x-4=12+15x
add 4 on both sides to get
17x=16+15x
now subtract 15x on both sides to get
2x=16
divide by 2 on both sides
you get
x=8

The LCM of x+3 and x-4 is x² - x - 12
Working out gives;

Simplify further using equations calculator to get the answer as attached below: