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Solve the related quadratic equation, plot the solutions on a number line, and test a value from each interval.
{x|x≠7}
To solve the quadratic inequality algebraically, we will follow three steps.
We will start by solving the related equation.
x^2-14x=- 49 ⇔ 1x^2+( - 14)x+ 49=0
Substitute values
The root of the equation is 7
The solution of the related equation is 7. Let's plot it on a number line. Since the original is a strict inequality, the point will be open.
Finally, we must test a value from each interval to see if it satisfies the original inequality. Let's choose a value from the first interval, x < 7. For simplicity, we will choose x=0.
x= 0
Calculate power
Zero Property of Multiplication
Identity Property of Addition
Since x=0 produced a true statement, the interval x < 7 is a part of the solution. Similarly, we can test the other interval.
| Interval | Test Value | Statement | Is It Part of the Solution? |
|---|---|---|---|
| x > 7 | 10 | - 40 > - 49 ✓ | Yes |
We can now write the solution set and show it on a number line. {x|x≠7} or (- ∞ , 7) ⋃ (7, + ∞)