Simplifying 
2x + 3 + 7x = -24 
 
Reorder the terms: 
3 + 2x + 7x = -24 
 
Combine like terms: 2x + 7x = 9x 
3 + 9x = -24 
 
Solving 
3 + 9x = -24 
 
Solving for variable 'x'. 
Move all terms containing x to the left, all other terms to the right. 
 Add '-3' to each side of the equation. 
3 + -3 + 9x = -24 + -3 
 Combine like terms: 3 + -3 = 0 
0 + 9x = -24 + -3 
9x = -24 + -3 
 Combine like terms: -24 + -3 = -27 
9x = -27 
 Divide each side by '9'. 
x = -3 
 Simplifying 
x = -3