Which of the following equations is of a parabola with a vertex at (1, -1)?
y= ( x - 1)2.1
y = ( x + 1)2 +1
y=(x + 1) 2-1
= (x - 1) 2+1

1. isolate the variable, in this case, d. subtract 35.5 on both sides of the equation.2. 52 subtracted by 35.5 is 16.53. therefore your answer would be d= 16.5this is the basics of pre algebra, isolating variable through adding, subtracting, multiplying, and dividing, if you have any other questions to ask just comment!

Igot the answer of 15.8 years.