11) \(\left(x-\dfrac{1}{2}\right)^2-\dfrac{1}{2}=-\dfrac{7}{16}\)
\(\left(x-\dfrac{1}{2}\right)^2=-\dfrac{7}{16}+\dfrac{1}{2}\)
\(\left(x-\dfrac{1}{2}\right)^2=\dfrac{1}{16}\)
\(x-\dfrac{1}{2}=\sqrt{\dfrac{1}{16}}\)
\(x-\dfrac{1}{2}=\dfrac{1}{4}\)
\(x=\dfrac{1}{4}+\dfrac{1}{2}\)
\(x=\dfrac{3}{4}\)
12) \(\left\{x^2-\left[6^2-\left(8^2-9.7\right)^3-7.5\right]^3\right\}=5.21-89\\ \left\{x^2-\left[36-\left(64-63\right)^3-35\right]^3\right\}=105-89\\ \left\{x^2-\left[36-\left(1\right)^3-35\right]^3\right\}=16\\ \left\{x^2-\left[36-1-35\right]^3\right\}=16\\ \left\{x^2-0^3\right\}=16\\ x^2-0=16\\ x^2=16+0\\ x^2=16\\ x^2=4^2\\ \Rightarrow x=2\)