Question 717712
We're in quadrant II, so x < 0


x^2 + y^2 = 1


x^2 + (1/4)^2 = 1


x^2 + 1/16 = 1


x^2 = 1 - 1/16


x^2 = 16/16 - 1/16


x^2 = 15/16


x = -sqrt(15/16)... remember, x < 0


x = -sqrt(15)/sqrt(16)


x = -sqrt(15)/4


So {{{x = -sqrt(15)/4}}}