SOLUTION: How do I get B in this Equation? r^2-br+49=0 A=1 B=? C=49

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Question 322299: How do I get B in this Equation?
r^2-br+49=0
A=1
B=?
C=49
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
r^2-br+49=0
When the above equation is a perfect square
(r-7)^2= r^2-2*7*1*r+49
compare the equation r^2-br+49
b=2*7*1
b=14