Question

In the polynomial p(x)=x²+ax+b, p(1)=4, p(2)=9. Find a and b. Also find p(3)​

Answer 1

Explanation:

p(x) = x²+ax+ b

p(1)=4

p(1)= 1²+a+b=4

a+b=3

b=3-a------1

p(2)=9

p(2)=2²+2a+b=9

2a+b=5

2a+3-a=5

a=2--------2

substitute 2 in 1

b= 3-2=1

p(3)= 3²+3a+b

=9+3(2)+1

= 9+6+1

=16