## anonymous 5 years ago determine two values of b that will make 64xcubed+bx+16 a perfect square trinomial

1. anonymous

$64x^3+b*x+16$

2. anonymous

a perfect square trinomial is a square of a binomial: $(a+b)^2$

3. anonymous

if i assume the equation to be 64x^2 + b*x + 16 --> (a + b)^2 = a^2 + 2*a*b + b^2

4. anonymous

ok b^2 = 16, so $\sqrt{16} = \pm$

5. anonymous

+/- 4

6. anonymous

a^2 = 64x^2, so let's keep a=8x.....now for the 2*a*b portion. we have a and b, but each value can be positive or negative....so the value are +/- 4 and +/- 8.

7. anonymous

so 2*a*b

8. anonymous

from your equation: [bx] = 2*a*b

9. anonymous

so b can vary between 2*(+/-4)*(+/-8)