Question

If the distance between (2,-3) and (10,y) is 10 ,then find y

Answer 1

let A (2,-3)
B(10 ,y)
distance between A and B = 10
√[(2-10)² + (-3 -y)²] = 10
√[(-8)² + (-3 -y)²] = 10
(-8)² + (-3 -y)² = (10)²
64 + 9 + y² +6y = 100
73 +  y² +6y = 100
y² +6y = 100 - 73
y²  +6y -27 = 0
y² +9y  -3y -27 = 0
y(y +9) -3(y +9) = 0
(y+9)(y-3) = 0

y+9 = 0 
y = -9 
and
y  -3 = 0
y = 3
y can be -9 and 3

Answer 2

hope u understand the solution