Answer:
x = 10°
Step-by-step explanation:
As we can see it is an equilateral triangle so all sides and angles are equal. 
6x + 6x + 6x = 180° { being sum of angles of triangle }
18x = 180°
x = 180° / 18
x = 10°
Hope it will help ✔
 
        
                    
             
        
        
        
Standard form: ax+by=c
With standard form there are a few rules One being ax and by cannot be fractions. Two being ax has to be positive.
Now ill explain the problem. 
y=-1/2x-5 ↔ You will need to multiply the whole problem by 2 which will leave you will this 2y=-2x-10
Next you will need to move x over to the y side which will look like this 2x+2y=-10 (your answer)
Now you might be asking where the - went that was in front of the x term. Another rule is when you move across the equal sign you change the sign.
Let me know if this helped!
 
        
             
        
        
        
Answer: x=−10
Explanation:
1.regroup terms:4−x=−2x−6
2.add 2x to both sides: 4−x+2x=−6
3. Simplify 4−x+2x to 4+x.:: 4+x=−6
4. Subtract 4 from both sides: x=−6−4
5. Simplify —6−4 to −10: x=−10