Imaginary zeros of polynomials

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Discussing the Relationship Between the Discriminant and X-intercepts on a Graph
Sketch and compare the following quadratic functions:
i)
$y=2{x^2} + x - 15$ $y = 2 x^{2} + x - 15$
ii)
$y=x^2+4x+4$ $y = x^{2} + 4 x + 4$
iii)
$y=2{x^2} + x + 15$ $y = 2 x^{2} + x + 15$
Locating the Regions of Imaginary Zeros on Polynomial Graphs
Indicate the region on the graphs where the non-real zeros occur.
i) $f\left( x \right) = \frac{1}{{10}}\left( {x + 2} \right)\left( {x - 1} \right)\left( {x - 3} \right)\left( {x - 5} \right)$ $f (x) = \frac{1}{10} (x + 2) (x - 1) (x - 3) (x - 5)$
ii) $g\left( x \right) = \frac{1}{{10}}\left( {x + 2} \right)\left( {x - 1} \right)\left( {{x^2} - 8x + 17} \right)$ $g (x) = \frac{1}{10} (x + 2) (x - 1) (x^{2} - 8 x + 17)$