`1` góc `90^o`

`=>` Tổng các góc là : `90xx4=360^o`

`=>C`

cj sửa lại rồi nhe.

\(\dfrac{5}{2}-\dfrac{3}{2}\cdot\left(x-2\right)=2\\ \Rightarrow\dfrac{5}{2}-\dfrac{3}{2}x+\dfrac{6}{2}=2\\ \Rightarrow\dfrac{5}{2}-\dfrac{3}{2}x=2-3\\ \Rightarrow\dfrac{5}{2}-\dfrac{3}{2}x=-1\\ \Rightarrow\dfrac{3}{2}x=\dfrac{5}{2}-\left(-1\right)\\ \Rightarrow\dfrac{3}{2}x=\dfrac{7}{2}\\ \Rightarrow x=\dfrac{7}{2}:\dfrac{3}{2}\\ \Rightarrow x=\dfrac{7}{3}\)

\(x^3:x=x^2\) ạ.

\(\left(3x+2\right)^3=512\\ \Rightarrow\left(3x+2\right)^3=8^3\\ \Rightarrow3x+2=8\\ \Rightarrow3x=8-2\\ \Rightarrow3x=6\\ \Rightarrow x=\dfrac{6}{3}\\ \Rightarrow x=2\)

Vậy `x=2`