12+6x was subtracted from the left but only 12 was subtracted from the right.
6x and 6 are not equal unless x=1
X=-11/15
The answer would be -84.
Here are the steps I did.
1. Simplify 4 + 8 to 12 ( -7 * 12 )
2. Now lastly simplify and u get -84.
3. -1
4. 19/4
hope i helped!
Slope of a Line Passing through two points (x₁ , y₁) and (x₂ , y₂) is given by :

Given Points are (1 , 7) and (-4 , -8)
here x₁ = 1 and x₂ = -4 and y₁ = 7 and y₂ = -8

3 is answer