SOLUTION: given that y^2+10y+k is a perfect square trinomial, find the value of k.

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Question 937033: given that y^2+10y+k is a perfect square trinomial, find the value of k.
Found 2 solutions by josgarithmetic, MathLover1:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Discriminant is 0.

10%5E2-4%2A1%2Ak=0

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

y%5E2%2B10y%2Bk is a perfect square trinomial,
to find the value of k use 10y and recall the rule %28a%2Bb%29%5E2=a%5E2%2B2ab%2Bb%5E2; so,in 10y we know that b=y and 2a=10=>a=5%29%0D%0A%0D%0Ausing+that+we+have+%0D%0A+%7B%7B%7B%28y%5E2%2B10y%2B_%29-_%2Bk
%28y%5E2%2B10y%2B5%5E2%29-25%2Bk
%28y%2B5%29%5E2-25%2Bk ...=> to have a perfect square trinomial k must be 25
%28y%2B5%29%5E2-25%2B25
%28y%2B5%29%5E2