To find the tangent line of the graph:
 ⇒ must find:
- point at which the tangent line touches the graph
- slope of the tangent line
Let's find the point at which the tangent line touches the graph:
 At x = -1, 
 

 Point: (-1,1)
Let's find the slope of the tangent line
 ⇒ get the derivation of function than plug (-1) in the x-position to get 
 the exact slope
 

 Slope of tangent line: 15
Now put all the calculated value into the point-slope form:
 

  --> point on the tangent line --> point on the tangent line
- m --> tangent slope's value
 So:
 

Thus the tangent line's equation is y = 15x + 16
Answer: y = 15x + 16
Hope that helps!