Is x=3 a function and or a relation?

Sara bought a pair of pants that were on sale for 30 percent off of the original price. if the original price of the pants was $29, what was the sales price of the pants?

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

100 points, hi, i’m not sure how to get the equation from the graph and table.