Let $\bar{a}, \bar{b}$ and $\bar{c}$ be non-coplanar vectors. If $\mathrm{P}, \mathrm{Q}, \mathrm{R}$ and…
Let $\bar{a}, \bar{b}$ and $\bar{c}$ be non-coplanar vectors. If $\mathrm{P}, \mathrm{Q}, \mathrm{R}$ and $\mathrm{S}$ are four points with position vectors $-\bar{a}+4 \bar{b}-3 \bar{c}, 3 \bar{a}+2 \bar{b}-5 \bar{c},-3 \bar{a}+8 \bar{b}-5 \bar{c}$ and $-3 \bar{a}+2 \bar{b}+\bar{c}$ respectively then the ordered pair $(x, y)$ of real numbers such that $\overline{P Q}=x \cdot \overline{P R}+y \cdot \overline{P S}$ is