Hey there!
64 + 8 = 72
so x = 8
Hope this helps
Have a great day (:
hello
the question here is
![3\sqrt[]{7}(14-4\sqrt[]{56})](https://tex.z-dn.net/?f=3%5Csqrt%5B%5D%7B7%7D%2814-4%5Csqrt%5B%5D%7B56%7D%29)
step 1
multiply through the bracket by the coeffiecient
![\begin{gathered} 3\sqrt[]{7}(14-4\sqrt[]{56}) \\ (3\sqrt[]{7}\times14)-(3\sqrt[]{7}\times4\sqrt[]{56}) \\ (14\times3\sqrt[]{7})-3\sqrt[]{7}\times4\sqrt[]{4\times14} \\ (42\sqrt[]{7})-3\sqrt[]{7}\times8\sqrt[]{14} \\ (42\sqrt[]{7})-\lbrack(3\times8)\sqrt[]{7\times14} \\ 42\sqrt[]{7}-24\sqrt[]{98} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%203%5Csqrt%5B%5D%7B7%7D%2814-4%5Csqrt%5B%5D%7B56%7D%29%20%5C%5C%20%283%5Csqrt%5B%5D%7B7%7D%5Ctimes14%29-%283%5Csqrt%5B%5D%7B7%7D%5Ctimes4%5Csqrt%5B%5D%7B56%7D%29%20%5C%5C%20%2814%5Ctimes3%5Csqrt%5B%5D%7B7%7D%29-3%5Csqrt%5B%5D%7B7%7D%5Ctimes4%5Csqrt%5B%5D%7B4%5Ctimes14%7D%20%5C%5C%20%2842%5Csqrt%5B%5D%7B7%7D%29-3%5Csqrt%5B%5D%7B7%7D%5Ctimes8%5Csqrt%5B%5D%7B14%7D%20%5C%5C%20%2842%5Csqrt%5B%5D%7B7%7D%29-%5Clbrack%283%5Ctimes8%29%5Csqrt%5B%5D%7B7%5Ctimes14%7D%20%5C%5C%2042%5Csqrt%5B%5D%7B7%7D-24%5Csqrt%5B%5D%7B98%7D%20%5Cend%7Bgathered%7D)
Your answer will be letter b
You can set it up like:
400/2.5 = 600/x; now cross multiply
400x = 2.5(600)
400x = 1,500; now divide both sides by 400 to isolate the x, and you get x = 3.75 hours