AB + CD = BC + DA 
<span>Where A, B, C, and D are points on the quad, and AB is the length of the line A to B, etc. </span>
<span>Since you know three sides, you can easily solve for the fourth. </span>
        
             
        
        
        
Answer:
x = -12
Step-by-step explanation:
Step 1: Subtract 2x from both sides
2x + 10 = -14
Step 2: Subtract 10 from both sides
2x = -24
Step 3: Divide both sides by 2
x = -12