1. **State the problem:** We have a triangle with interior angles $35^\circ$, $(5x + 7)^\circ$, and $(9x - 2)^\circ$. We need to find $x$ and the measure of the angle $(5x + 7)^\circ$.
2. **Formula:** The sum of interior angles in any triangle is always $180^\circ$. So,
$$35 + (5x + 7) + (9x - 2) = 180$$
3. **Simplify the equation:**
$$35 + 5x + 7 + 9x - 2 = 180$$
$$35 + 7 - 2 + 5x + 9x = 180$$
$$40 + 14x = 180$$
4. **Isolate $x$:**
$$14x = 180 - 40$$
$$14x = 140$$
5. **Divide both sides by 14:**
$$x = \cancel{\frac{14x}{14}} = \frac{140}{\cancel{14}}$$
$$x = 10$$
6. **Find the measure of the indicated angle $m\angle X = (5x + 7)^\circ$:**
$$m\angle X = 5(10) + 7 = 50 + 7 = 57^\circ$$
**Final answers:**
$$x = 10$$
$$m\angle X = 57^\circ$$
Triangle Angles Bab3Ce
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