Question

question 15 the measures of the angles of a triangle are shown in the figure below. solve for x.

Explanation:

Step1: 三角形内角和为180°

$80^{\circ}+38^{\circ}+(5x + 12)^{\circ}=180^{\circ}$

Step2: 化简等式左边

$130^{\circ}+5x=180^{\circ}$

Step3: 移项求解

$5x=180^{\circ}- 130^{\circ}$
$5x = 50^{\circ}$
$x = 10^{\circ}$

Answer:

$x = 10$