calculus question

Question

 

Question Number 4?

Answer 1

a=2,b=3.

option A.

if function is differentiable then continous also.

so b*(-1)*(-1)+a(-1)+4=a(-1)(-1)+b

a=2.

and also differentiable.

so

2b(-1)+a=2a(-1)

-2b= -3a

b=3.