Answer:
The first one is -3 
The second one is 2
Step-by-step explanation:
 
        
             
        
        
        
Step-by-step explanation:
6x - 3x^2 + 2x^2 -2x = 5x^2 + 15x 
4x -x^2 = 5x^2 + 15x 
-11x - 6x^2 = 0 
-6x^2 - 11x = 0 
use the quadratic formula 
(-b±√(b²-4ac))/(2a)
 
        
                    
             
        
        
        
11. 5x^2-30=0 
+30 to both sides 
5x^2=30
÷5 both sides 
x^2=6
 square root both sides 
x= +square root 6 ,- square root 6
12. 4x^2+10=26
-10 both sides 
4x^2=16
÷4 both sides 
x^2=4
square root both sides 
x=+2,-2
13. a=72yrd^2
l=2w
w=?
a=l×w
72=2w×w
72=2w^2
÷2 both sides 
36=w^2
square root both sides 
w=+6,-6 
a measurement can't be - so w=6 
Plug into l=2w 
l=2×6
l=12
w=6