Math
posted by Shadow .
What positive value of b makes 9^2bx+4 a perfect square trinomial? How would you solve this problem? Thanks

9x^2bx+4

First of all to be a perfect square, the first and last terms should be perfect squares, and they are!
so it looks like we had
(3x ± 2)^2
for (3x+2)^2 we would get 9x^2 + 12x + 4
so bx = 12x
b = 12
for (3x  2)^2 we would get 9x^2  12x + 4
so bx = 12x
b = 12
So b = ± 12 
Thank you!

Welcome
Respond to this Question
Similar Questions

math,help
Is this trinomial a perfect square x^26x+9 if the trinomial starts with x^2 and 1/2 of the middle term coefficient squared equals the last term, then it is a perfect square. tell me what you found. i thought it was not a perfect square. … 
Algebra
1)Solve by factoring:5x^2=419x answer=4,1/5 2)Which quadratic equation has roots 7 and 2/3? 
algebra
1)Solve by factoring:5x^2=419x answer=4,1/5 2)Which quadratic equation has roots 7 and 2/3? 
math 118
x^2+10x Add the proper constant to the binomial so tha tthe resulting trinomial is a perfect square trinomial. Then factor the trinomial 
Algebra 2
Find the value of c that makes the expression a perfect square trinomial. Then write the expression as the square of a binomial. I didn't really understand what that meant. x^223x+c x^2(2/7)x+c 
Algebra 1
1. What is the excluded value for the rational expression x^2  4/3x  6? 
Math
The value of k that makes the expression x^2 + 72x +k a perfect square trinomial is ? 
algebra 2
find the value of c that makes each trinomial a perfect square. then write the trinomial as a prefect square. x^210x+c x^2+60x+c 
10th algebra
x2+22x +c find the value of c that makes the trinomial a perfect square 
easy math
What value of c makes x^2 + 6x + c a perfect square trinomial?