there is no B i see A and -5A unless its for -5A??
 
        
             
        
        
        
Here is one way to solve for x.
Step 1)  2x^2-7=9
Step 2)  2x^2-7+7=9+7
Step 3)  2x^2=16
Step 4)  (2x^2)/2=16/2
Step 5)  x^2=8
Step 6)  sqrt(x^2)=sqrt(8)
Step 7)  |x|=sqrt(8)
Step 8)  x=sqrt(8) or x=-sqrt(8)
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Below are explanations/reasons to each of the steps above.
Step 1) Original equation
Step 2) Add 7 to both sides
Step 3) Combine like terms
Step 4) Divide both sides by 2
Step 5) Simplify
Step 6) Apply the square root to both sides. The notation "sqrt" is shorthand for "square root"
Step 7) Use the rule that sqrt(x^2) = |x| for all real numbers x
Step 8) Use the rule that if |x| = k then x = k or x = -k for some fixed number k.
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The two solutions are
x = sqrt(8) or x = -sqrt(8)
        
             
        
        
        
If it goes from a higher number to a lower number it is a decrease.
(15,295 - 9182) / 15295....x 100
6113 / 15295 = 0.399....x 100 = 39.9% decrease
        
             
        
        
        
23=4w-13
First add 13 to both sides.
36=4w
w=9 
Hope this helps!