Answer:
There are NO real roots for this equation. The only roots have imaginary parts and therefore cannot be represented on the real x-axis.
Step-by-step explanation:
We notice that the expression on the left of the equation is a quadratic with leading term
, which means that its graph is that of a parabola with branches going up.
Therefore, there can be three different situations:
1) if its vertex is ON the x axis, there would be one unique real solution (root) to the equation.
2) if its vertex is below the x-axis, the parabola's branches are forced to cross it at two locations, giving then two real solutions (roots) to the equation.
3) if its vertex is above the x-axis, it will have NO real solutions (roots) but only non-real ones.
So we proceed to examine the vertex's location, which is also a great way to decide on which set of points to use in order to plot its graph efficiently.
We recall that the x-position of the vertex for a quadratic function of the form
is given by the expression:
![x_v=\frac{-b}{2a}](https://tex.z-dn.net/?f=x_v%3D%5Cfrac%7B-b%7D%7B2a%7D)
Since in our case
and
, we get that the x-position of the vertex is:
![x_v=\frac{-b}{2a}\\x_v=\frac{-(-3)}{2(2)}\\x_v=\frac{3}{4}](https://tex.z-dn.net/?f=x_v%3D%5Cfrac%7B-b%7D%7B2a%7D%5C%5Cx_v%3D%5Cfrac%7B-%28-3%29%7D%7B2%282%29%7D%5C%5Cx_v%3D%5Cfrac%7B3%7D%7B4%7D)
Now we can find the y-value of the vertex by evaluating this quadratic expression for x = 3/4:
![y_v=f(\frac{3}{4})=2( \frac{3}{4})^2-3(\frac{3}{4})+4\\f(\frac{3}{4})=2( \frac{9}{16})-\frac{9}{4}+4\\f(\frac{3}{4})=\frac{9}{8}-\frac{9}{4}+4\\f(\frac{3}{4})=\frac{9}{8}-\frac{18}{8}+\frac{32}{8}\\f(\frac{3}{4})=\frac{23}{8}](https://tex.z-dn.net/?f=y_v%3Df%28%5Cfrac%7B3%7D%7B4%7D%29%3D2%28%20%5Cfrac%7B3%7D%7B4%7D%29%5E2-3%28%5Cfrac%7B3%7D%7B4%7D%29%2B4%5C%5Cf%28%5Cfrac%7B3%7D%7B4%7D%29%3D2%28%20%5Cfrac%7B9%7D%7B16%7D%29-%5Cfrac%7B9%7D%7B4%7D%2B4%5C%5Cf%28%5Cfrac%7B3%7D%7B4%7D%29%3D%5Cfrac%7B9%7D%7B8%7D-%5Cfrac%7B9%7D%7B4%7D%2B4%5C%5Cf%28%5Cfrac%7B3%7D%7B4%7D%29%3D%5Cfrac%7B9%7D%7B8%7D-%5Cfrac%7B18%7D%7B8%7D%2B%5Cfrac%7B32%7D%7B8%7D%5C%5Cf%28%5Cfrac%7B3%7D%7B4%7D%29%3D%5Cfrac%7B23%7D%7B8%7D)
This is a positive value for y, therefore we are in the situation where there is NO x-axis crossing of the parabola's graph, and therefore no real roots.
We can though estimate a few more points of the parabola's graph in order to complete the graph as requested in the problem. For such we select a couple of x-values to the right of the vertex, and a couple to the right so we can draw the branches. For example: x = 1, and x = 2 to the right; and x = 0 and x = -1 to the left of the vertex:
![f(-1) = 2(-1)^2-3(-1)+4= 2+3+4=9\\f(0)=2(0)^2-3(0)+4=0+0+4=4\\f(1)=2(1)^2-3(-1)+4=2-3+4=3\\f(2)=2(2)^2-3(2)+4=8-6+4=6](https://tex.z-dn.net/?f=f%28-1%29%20%3D%202%28-1%29%5E2-3%28-1%29%2B4%3D%202%2B3%2B4%3D9%5C%5Cf%280%29%3D2%280%29%5E2-3%280%29%2B4%3D0%2B0%2B4%3D4%5C%5Cf%281%29%3D2%281%29%5E2-3%28-1%29%2B4%3D2-3%2B4%3D3%5C%5Cf%282%29%3D2%282%29%5E2-3%282%29%2B4%3D8-6%2B4%3D6)
See the graph produced in the attached image.