D because the y-intercept is at -5 like shown in the equation, and the slope equals to 1, and I do believe that the bold line means that it is less than or equal to, just like the equation says.
Substitute
, so that

Then the resulting ODE in
is separable, with

On the left, we can split into partial fractions:

Integrating both sides gives




Now solve for
:


To solve this, you would do:
x + 75% * x = 35
7/4 * x = 35
x = 20
Im pretty sure tge answers -1.68426