Chapter 2 - Differentiation - 2.2 Exercises - Page 114: 56

$y=-x-3$

$y=(x-2)(x^{2}+3x)$ $y=x^{3}+3x^{2}-2x^{2}-6x$ $y=x^{3}+x^{2}-6x$ $y'=3x^{2}+2x-6$ $y'=f’(1)=3(1)^{2}+2(1)-6$ $y'=3+2-6$ $y’=-1$ use equation of a straight line $y-y_{1}=m(x-x_{1})$ $y-(-4)=-1(x-1)$ $y+4=-x+1$ $y=-x-3$