Question

Find the value of ax²+bx+c at x=-b/a

Answer 1

p(x)=ax2+bx+c
p(-b/a)=a(-b/a)2+b(-b/a)+c
=a×b2/a2-b2/a+c
=b2/a-b2/a+c
=c

Answer 2

Hope this helps you.