SOLUTION: the perimeter of a triangle is 39ft. the first side is 3ft more than twice the second side. the third side is 4ft less than twice the second. find the measure of the longest side

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Question 188896: the perimeter of a triangle is 39ft. the first side is 3ft more than twice the second side. the third side is 4ft less than twice the second. find the measure of the longest side
Answer by Mathtut(3670) About Me  (Show Source):
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lets call our sides a, b ,and c.....so we have P=39..and we have a=2b+3 and c=2b-4.......find longest side
:
P=a+b+c..........eq 1
a=2b+3...........eq 2
c=2b-4...........eq 3
P=39.............eq 4
:
lets plug the values of a from eq 2 , c from eq 3 ,and P from eq 4 into eq 1
:
39=2b+3+b+2b-4
:
5b=40
:
b=8
:
a=2(8)+3=19
:
c=2(8)-4=12
:
longest side is a=19