y=-4x²+4x-1 this quadratic equation is of the form ax² + bx + c
and its discriminante is ( Δ = b²- 4ac)
:
So Δ = b² 4ac ==> (4)² - 4(-4)(-1)==> (16) -16 = 0
When Δ = 0, the parabola intercept x=axis in one & only one point
And the x-intercept = -b/2a = (-4)/[2.(-4)] ==> x = 1/2