Answer:
y = 
Step-by-step explanation:
Given
x(y + 2) = 3x + y ← distribute parenthesis on left side
xy + 2x = 3x + y ( subtract 2x from both sides )
xy = x + y ( subtract y from both sides )
xy - y = x ← factor out y from each term on the left side )
y(x - 1) = x ← divide both sides by (x - 1)
y = 
In triangle, ABD,
AD²= AB²+BD²
AB² = AD²-BD²
AB² = 18²-9² = 324-81 = 243
AB = √243
In triangle, ABC,
AC² = AB²+BC²
AC² = (√243)²+(13)²
AC² = 243+169
AC = √412
AC = 20.29
The entry in row 1, column 1 of
is

(i.e. the dot product of row 1 of
and column 1 of
)
The entry in row 1, column 2 of
is

The second option is the correct answer.
Just substitute it into the gradient formula which is: y2 - y1 / x2 - x1. So 2-3/2-9 = -1/-7 = 1/7