Sprendimas: nqsTcq - 1

 x1* x2+ y1* y2  = 
0
 x1* x2+ y1* y2 = 0$$x1\cdot x2+y1\cdot y2$$ = $$0$$
 x1* x2 = 0- y1* y2$$x1\cdot x2$$ = $$0-y1\cdot y2$$
 x1* x2 = - y1* y2$$x1\cdot x2$$ = $$-y1\cdot y2$$
x1 = - 
 y1* y2
/ x2
$$x1$$ = $$-\frac{y1\cdot y2}{x2}$$