Roots and Negatives

GRE Quant Problem Solving
1

Basically ETS considers √64 = 8 but if one quantity is 2 and the other quantity asks for possible values then Quantity b is greater.

Then comes if x=√14 and y^2 =14 ,how come y is greater than b when asked for possible values?? Can’t both x and y equal?? I’m a bit confused

2

If y^2 = 14, y can be -\sqrt{14}.

3

@Tishi Note in Leaderboard’s example that \sqrt{14} is still positive.

In the GRE, \sqrt{64} means |\sqrt{64}|, which is always 8.

However, if an equation said that x^2=64, then we have the following:

  • x=\sqrt{64} → x=|\sqrt{64}| → x=8
  • x=-\sqrt{64} → x=-|\sqrt{64}| → x=-8

Note that \sqrt{64} always equals 8.

1 Like
4

Got it, thanks