Answer:
x=-6
Step-by-step explanation:
1. Collect like terms [-15x] [+6x]
-15x+10+6x=64
-9x+10=64
2. Move constant [+10] to the right-hand side and change its sign
-9x+10=64
-9x=64-10
3. Subtract the numbers [64-10]
-9x=64-10
-9x=54
4. Divide both sides of the equation by -9
-9x/9=54/9
5. Solution
x=-6