13. Five marks example problems VII

1. Calculate the distance between the points $A(7, 3)$ and $B$ which lies on the $x$-axis whose abscissa is $11$.

 

Distance $=$  units

 

 

2. Find the value of '$a$' such that $PQ = QR$ where $P$, $Q$ and $R$ are the points whose coordinates are $(6, -1)$, $(1, 3)$ and $(a, 8)$ respectively.

 

$a=i$ or $a=i$

 

[Note: Enter the number from greatest to smallest]