Question

1. 9x - 73 74° 74° 3x + 23

Explanation:

Step1: Recall angle - sum property of a triangle

The sum of the interior angles of a triangle is 180°. So, we set up the equation $(9x - 73)+(3x + 23)+74=180$.

Step2: Combine like - terms

First, combine the $x$ terms and the constant terms on the left - hand side: $(9x+3x)+(-73 + 23+74)=180$, which simplifies to $12x+( - 50 + 74)=180$, and further to $12x + 24=180$.

Step3: Isolate the variable term

Subtract 24 from both sides of the equation: $12x+24 - 24=180 - 24$, resulting in $12x=156$.

Step4: Solve for $x$

Divide both sides of the equation by 12: $\frac{12x}{12}=\frac{156}{12}$, so $x = 13$.

Answer:

$x = 13$