Is it possible to express accuracy knowing sensitivity and specificity? 
I know the value of the sensitivity Se and the value of the specificity of Sp, they are equal to 78.65 and 90.00, respectively. I know nothing but this. Can I somehow of the equations, which in the photo express the value of the accuracy Ac? 

Consider
$$X = \frac{A}{A+B}, \ Y = \frac{C}{C+D}, \ Z = \frac{A+C}{A+B+C+D}$$
Then $X$ and $Y$ don't determine $Z$. Counterexample:
$$A=1, B = 2, C = 3, D = 9 \Rightarrow X = \frac{1}{3}, Y = \frac{1}{4}, Z = \frac{4}{15}$$
$$A=3, B = 6, C = 1, D = 3 \Rightarrow X = \frac{1}{3}, Y = \frac{1}{4}, Z = \frac{4}{13}$$
