P(-1, 1) & Q(5, -7)
By distance formula:- \(\sqrt{(x_2-x_1)^2 + (y_2-y_1)^2}\)
d(PQ) = \(\sqrt{[5-(-1)]^2 + [-7-1]^2}\)
= \(\sqrt{(5+1)^2 + (-7-1)^2}\)
= \(\sqrt{6^2+(-8)^2}\)
= \(\sqrt{36 + 64}\)
= \(\sqrt{100}\)
= 10 sq.units
∴ The distance between P(-1, 1) & Q(5 -7) is 10 sq.units.