Answer:
x = (3 + 8y) / (y - 1)
Explanation:
y = (x + 3) / (x - 8)
Make x the subject
y = (x + 3) / (x - 8)
Cross product
y * (x - 8) = (x + 3)
xy - 8y = x + 3
xy - x = 3 + 8y
Factorize the left hand side of the equation
x( y - 1) = 3 + 8y
Divide both sides by (y - 1)
x = (3 + 8y) / (y - 1)