1. **State the problem:**
We want to prove that $$2x^2 + 2x > -4$$ for all real values of $$x$$, and then explain why the graph of $$y = 2x^2 + 2x + 4$$ has no x-intercepts.
2. **Rewrite the inequality:**
Start with the given inequality:
$$2x^2 + 2x > -4$$
Divide both sides by 2:
$$\cancel{2}x^2 + \cancel{2}x > \frac{-4}{\cancel{2}}$$
which simplifies to
$$x^2 + x > -2$$
3. **Complete the square:**
Recall the formula for completing the square:
$$x^2 + bx = (x + \frac{b}{2})^2 - \left(\frac{b}{2}\right)^2$$
Here, $$b = 1$$, so
$$x^2 + x = \left(x + \frac{1}{2}\right)^2 - \left(\frac{1}{2}\right)^2 = \left(x + \frac{1}{2}\right)^2 - \frac{1}{4}$$
4. **Substitute back into the inequality:**
$$\left(x + \frac{1}{2}\right)^2 - \frac{1}{4} > -2$$
Add $$\frac{1}{4}$$ to both sides:
$$\left(x + \frac{1}{2}\right)^2 > -2 + \frac{1}{4} = -\frac{7}{4}$$
5. **Analyze the inequality:**
Since $$\left(x + \frac{1}{2}\right)^2$$ is a square, it is always $$\geq 0$$ for all real $$x$$.
Because $$0 > -\frac{7}{4}$$, the inequality
$$\left(x + \frac{1}{2}\right)^2 > -\frac{7}{4}$$
is true for all real $$x$$.
6. **Multiply back by 2:**
Recall the original inequality was
$$2x^2 + 2x > -4$$
which we have shown is true for all real $$x$$.
7. **Explain why $$y = 2x^2 + 2x + 4$$ has no x-intercepts:**
The x-intercepts occur where $$y=0$$:
$$2x^2 + 2x + 4 = 0$$
Rewrite as
$$2x^2 + 2x = -4$$
But from step 6, we know $$2x^2 + 2x > -4$$ for all $$x$$, so the left side is always greater than $$-4$$.
Therefore, the equation $$2x^2 + 2x + 4 = 0$$ has no real solutions, meaning the graph does not cross the x-axis and has no x-intercepts.
**Final answer:**
$$2x^2 + 2x > -4$$ for all real $$x$$, so $$y = 2x^2 + 2x + 4$$ has no x-intercepts.
Quadratic No X Intercepts F30Cff
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