Question 83166The general expression for a quadratic in completed square form is: {{{y=a(x+b)^2+c}}} where the vertex would be (-b,c). 1) Since the vertex is (-8,4), then the formula should be: {{{y=a(x+8)^2+4}}} And to find the value of a, substitute the other point (-6,-2) in the equation: {{{-2=4a+4}}} giving the value of a as {{{-3/2=-1.5}}} 2) To change a normal quadratic into the completed square form, first take half the coefficient of x (2) and place it in a bracket like this: {{{(x+2)^2}}} Now this expression gives you {{{x^2+4x+4}}} and since we only need the first two terms, we need to eliminate the last one. To do that you simply subtract 4: {{{(x+2)^2-4}}} And finally place the last term right after that. {{{(x+2)^2-4-1=(x+2)^2-5}}} This means the vertex is (-2,-5) 3) Same as the first one, and to make a quadratic function "open down" you will need to put a negative sign before the bracket: {{{-(x+2)^2+7}}} or {{{7-(x+2)^2}}}