Question

Выразить икс:
(a-x)*(b-x)=x^2

Answer 1

(a-x)*(b-x)=x^2;

ab - bx - ax + x^2 = x^2;

ax + bx = ab;

x(a+b) = ab;

x = ab/(a+b);

Answer 2

как-то так 

$(a-x)(b-x)= x^{2} \\ ab-ax-bx+ x^{2} = x^{2} \\ ab-ax-bx= x^{2} - x^{2} \\ ab-ax-bx=0 \\ -ax-bx=-ab/*(-1) \\ ax+bx=ab \\ x(a+b)=ab \\ x= \frac{ab}{a+b}$