Can you please clarify what you want to ask? Thanks!
Answer:
15
Step-by-step explanation:
18-x=3
18-3=x
18-3=15
First find the slope, take derivative of both sides with respect to x.
2y dy/dx=3x^2+6x
solve for dy/dx
dy/dx=[3x^2+6x]/2y
plug in given vales of (1,2(
dy/dx=9/4
now you have everything you need to plug into point slope form
y-2=(9/4)(x-1)
answer is y=(9/4)x+(1/4)