y = a(x-h)^2 + k
H = to the x-intercept
K = to the y-intercept.
And remember the flow chart that if your 'a' must be equal to 1 before u continue the 'completing the square' hence, you must factorise the 'a' first, to put the coefficient outside of the bracket so you could have the remaining of a=1 and carry on the 'completing the square' to solve the equation.
Also remember these few important key points in this chapter.
Sorry for the bad quality photos XD Keep practicing the applications of these formulas and ull do well. Just understanding is not enough! Hope this is helpful. All the best for the results for the rest of your tests! :D