Gabrielle's age is 3x (in which x is mikhail's age)
the sum is 56 so 3x+x=56
3x+x=56
4x=56
x=14
since x was mikhail's age, mikhail is 14 years old
It rises to the right so the slope is negative
Slope = rise / run = 18 / -9 = -2
The y intercept is at y = -3 so using the form y = mx + b we get
y = -2x - 3 which is option B (answer)