Question

qual o valor do x:
x/2+140°=180°

Answer 1

$\frac{x}{2}+140^o=180^o\\ \\ x+280^o=360^o\\ \\ x=360^o - 280^o\\ \\ x=80^o$

Answer 2

$\dfrac{x}{2}+140=180$

Multiplique os dois lados por 2:

$2\cdot\left(\dfrac{x}{2}+140\right)=2\cdot180$

$x+280=360$

$x=360-280$

$x=80^{\circ}$