Put the equation into the form y = ( x − h )^2 + k
Given equation is
We apply completing the square method
we take coefficient of middle term and then divide by 2 and then square it
coefficient of middle term is 26
Divide by 2, it becomes 13
then we square it (13)^2 = 169
Add and subtract 169
We got the equation in vertex form
If the number of days is d and he writes 3 pages for every d, then we can say
3d = 81