Answer:
the anwser is A
Step-by-step explanation:
i understand
very well and i just took that lesson
2*wm +140 = 1,250
2*wm = 1,110
Washington Monument = 555 feet tall
Answer:
n = 59
Step-by-step explanation:
There's definitely a better way, i just did math randomly but here goes:
First i squared both sides. which gets you:
![(\sqrt{n+5}-\sqrt{n-10} )(\sqrt{n+5}-\sqrt{n-10} )=1^2\\\\n+5 -2\sqrt{(n+5)(n-10)} +n-10=1](https://tex.z-dn.net/?f=%28%5Csqrt%7Bn%2B5%7D-%5Csqrt%7Bn-10%7D%20%29%28%5Csqrt%7Bn%2B5%7D-%5Csqrt%7Bn-10%7D%20%29%3D1%5E2%5C%5C%5C%5Cn%2B5%20-2%5Csqrt%7B%28n%2B5%29%28n-10%29%7D%20%2Bn-10%3D1)
Cleaning this up gives you:
![2n-5 -2\sqrt{(n+5)(n-10)}=1](https://tex.z-dn.net/?f=2n-5%20-2%5Csqrt%7B%28n%2B5%29%28n-10%29%7D%3D1)
Now move everything to the other side so we can square this equation again
![-2\sqrt{(n+5)(n-10)}=-2n+6](https://tex.z-dn.net/?f=-2%5Csqrt%7B%28n%2B5%29%28n-10%29%7D%3D-2n%2B6)
Divide both sides by -2
![\sqrt{(n+5)(n-10)}=n-3](https://tex.z-dn.net/?f=%5Csqrt%7B%28n%2B5%29%28n-10%29%7D%3Dn-3)
square again
![(n+5)(n-10)=(n-3)^2\\n^2-5n-50=n^2-6n+9](https://tex.z-dn.net/?f=%28n%2B5%29%28n-10%29%3D%28n-3%29%5E2%5C%5Cn%5E2-5n-50%3Dn%5E2-6n%2B9)
subtract n^2 from both sides, add 6n, and add 50
![-5n-50=-6n+9\\n-50 = 9\\n=59](https://tex.z-dn.net/?f=-5n-50%3D-6n%2B9%5C%5Cn-50%20%3D%209%5C%5Cn%3D59)
Put this back into the equation and you get a correct answer!
sqrt(59 + 5) = sqrt(64) = 8
sqrt(59-10) = sqrt(49) = 7
8 - 7 = 1