g = girls in class
b= boys in class
g = 2b-1
girls + boys =26
g+b=26
substitute g = 2b-1
2b-1 +b =26
combine like terms
3b-1 =26
add 1 to each side
3b -1+1 = 26+1
3b = 27
divide each side by 3
3b/3 = 27/3
b = 9
There are 9 boys
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