Intuition behind square rooting in a quadratic

[untold oxide]

f(x) = 8x^2 + 16x + 3

y = 0 when intercepting the x-axis, so to find the x-intercepts, f(x) = 0
0 = 8x^2 + 16x + 3
0/8 = 0 = x^2 + 2x + 0.375
0 = (x+1)^2 + 0.375 - 1
sqrt(0) = 0 = sqrt( (x+1)^2 + (0.375 - 1) )
0 = x + 1 + 0.790 AND 0 = x + 1 - 0.790

this leads me to my Q (see below):

[obtuse galleon]

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[untold oxide]

$\sqrt{(x+1)^2}=+(x+1) \ \text{whereas }\sqrt{0.375-1} = \pm 0.790 \ \text{why is this? or am i mistaken for assuming (x+1) is positive after being square rooted?}$

[trail rivet]

odin4252

[tropic pier]

Not quite sure what you mean.
The solutions of x^2 = a are x = √(a) and x = -√(a). So, if (x + 1)^2 = 5/8, then x + 1 = ±√(10)/4.

[untold oxide]

i think i messed up my wording of the Q - its ok, ill come back if im caught lacking :D

+close