Rewrite in vertex form y=x^2+14x+50

i also need the work

Take half of the x coefficient -14 to get -7 . In other words, . (1/2) x (-14) = - 7
Now square -7 to get 49. In other words,  (-7)^2=(-7) x (-7) = 49
x^2 - 14x+49-49+50 .Now add and subtract 49 . Make sure to place this after the "x" term. Notice how 49 -49 = 0. So the expression is not changed. Group the first three terms. 
Factor  to get . 
Combine like terms. 
So after completing the square,  transforms to . So . 
So  is equivalent to . 
So the equation  is now in vertex form  where , , and  
Remember, the vertex of  is (h,k). 
So the vertex of  is (7,1). 

It would be 18 cm