For perpendicular lines, the product of their slopes is -1, i.e. m1m2 = -1 => m2 = -1/m1
Line y = -x - 5 has a slope of -1, therefore, the required line will have a slope of -1/-1 = 1.
Required equation is
y - 7 = (x - (-1))
y - 7 = x + 1
y = x + 1 + 7
y = x + 8
