Question

Find the values of y for which the distance between the points P (2, - 3) and Q (10, y) is 10 units

• A. $y=3or9$
• B. $y=3or-9$
• C. $y=-3or-9$
• D. $y=-3or9$

Answer 1

The correct option is B $y=3or-9$

It is given that the distance between (2, - 3) and (10, y) is 10.
Therefore, $\sqrt{(2-10{)}^2+(-3-y{)}^2}=10$
$\sqrt{(-8{)}^2+(3+y{)}^2}=10$
$64+(y+3{)}^2=100$
$(y+3{)}^2=36$
$y+3=\pm 6$
$y+3=+6ory+3=-6$
Therefore, $y=3or-9$