Combine like terms.
Since 7x and 6x both have a variable of x, you can combine them.
After that, you are left with:
You also have two numbers without variables; 11 and 3. You can also combine those.
So, your final answer would be:
1.3+-2.4= -1.1 hope I helped :)
The equation is
5x - 13 = 3x + 21
when solved, we get
x = 17