Help with 1-4 please

What is the equation of the following graph in vertex form? parabolic function going down from the left through the point zero comma twelve and through the point two comma zero and turning at the point four comma negative four and going up through the point six comma zero and continuing towards infinity courtesy of texas instruments a: y = (x − 4)2 − 4 b: y = (x + 4)2 − 4 c: y = (x + 2)2 + 6 d: y = (x + 2)2 + 12

Me find the value of x each figure.

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /