## Alexandra-morales24 3 years ago Given the following perfect square trinomial, fill in the missing term. (Do not type the variable in the blank.) 4x2 + ___x + 49

1. cwrw238

the two square roots involved are 2 and 7 so arithmetic on these will give you the missing number

2. amistre64

well, our options for this would suggest that: (2x)^2 + nx + (7)^2 comes form either: (2x+7)^2 or (2x-7)^2 ; the + on the middle term would indicate the first

3. Savvy

since 49 is apart of the square a term must be its square root i.e. 7 and sincce the other square term is 4x^2...then the term before squaring must be its square root i.e. 2x... so (2x + 7)^2 = 4x^2 + 28x + 49

4. ZhangYan

The answer would be 4x^2+ 14x+49 You take the square root of 49 and then take that answer (which is 7) and multiply it by 2. Hope this helps!

5. amistre64

Zhang, that only works if the first term is an x^2; we got a 4 in the way this time to do that we would have to divide off the 4 and work it out

6. amistre64

but, i spose the wrong answer is the best answer :) lol

7. amistre64

yes, it is

8. amistre64

(2x+7)^2 = 4x^2 +28x + 49

9. ZhangYan

@amistre64 is my answer is wrong??

10. amistre64

you should be able to dbl chk it to determine that, but as is, your answer is wrong. You did not account for the 4 on the first term

11. ZhangYan

oh right lol sorry it was 28

12. amistre64

(ax+b)^2 = (ax)^2 + 2ab x + b^2 sqrt(b^2) * 2 = 2b but that only works if a=1, otherwise we have to adjust it for a