Question

If one zeros of the polynomial x^2 +( a+1)x-6 is 2 find a

Answer 1

X^2+(a+1)x-6=0
Putting x=2
2^2+(a+1)2-6=0
4+2a+2-6=0
6+2a-6=0
2a=0
a=0

Answer 2

p(x) = x² + [a+1 ] x - 6

p[2] = 2² + [a + 1 ] × 2 - 6
       = 4 + 2a + 2 - 6 = 0
       =6 - 6 + 2a = 0
2a = 0
a = 0/2 = 0