The water levels at high tide was 9 feet and 1 foot at low tide
The factors of 49 are: 1, 7 and 49.
The factors of 50 are: 1, 2, 5, 10, 25 and 50.
The common factor is 1.
We have to solve this equation:

Third degree polynomials like this one are not easily solved, but this one has a root at x = 0. The let us factorize this polynomial as x times a second degree polynomial:

Now we can find the roots of the quadratic polynomial as:
![\begin{gathered} x=\frac{-(-6)\pm\sqrt[]{(-6)^2-4\cdot1\cdot6}}{2\cdot1} \\ x=\frac{6\pm\sqrt[]{36-24}}{2} \\ x=\frac{6\pm\sqrt[]{12}}{2} \\ x=\frac{6\pm\sqrt[]{4\cdot3}}{2} \\ x=\frac{6\pm2\sqrt[]{3}}{2} \\ x=3\pm\sqrt[]{3} \\ x_1=3-\sqrt[]{3} \\ x_2=3+\sqrt[]{3} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20x%3D%5Cfrac%7B-%28-6%29%5Cpm%5Csqrt%5B%5D%7B%28-6%29%5E2-4%5Ccdot1%5Ccdot6%7D%7D%7B2%5Ccdot1%7D%20%5C%5C%20x%3D%5Cfrac%7B6%5Cpm%5Csqrt%5B%5D%7B36-24%7D%7D%7B2%7D%20%5C%5C%20x%3D%5Cfrac%7B6%5Cpm%5Csqrt%5B%5D%7B12%7D%7D%7B2%7D%20%5C%5C%20x%3D%5Cfrac%7B6%5Cpm%5Csqrt%5B%5D%7B4%5Ccdot3%7D%7D%7B2%7D%20%5C%5C%20x%3D%5Cfrac%7B6%5Cpm2%5Csqrt%5B%5D%7B3%7D%7D%7B2%7D%20%5C%5C%20x%3D3%5Cpm%5Csqrt%5B%5D%7B3%7D%20%5C%5C%20x_1%3D3-%5Csqrt%5B%5D%7B3%7D%20%5C%5C%20x_2%3D3%2B%5Csqrt%5B%5D%7B3%7D%20%5Cend%7Bgathered%7D)
Then, the solutions to the equation are:
x = 0
x = 3 - √3
x = 3 + √3
Answer is b hope this helps you
Since all straight lines have an angle of 180 degrees if the exterior angle is equal to 113 degrees than you just subtract 113 from 180 which will equal 67.