Question

Find b and c if (2, -3) is the vertex of f(x) = 2x^2 + bx + c

Answer 1

f(2)=8+2b+c=0 ------ 2b+c= -8
f(-3)=2*9 -3b+c=0 --- -3b+c= -18

2b+c= -8
3b-c= 18
---------
5b 0 = 10

b= 10/5
b=2

2*2+c= -8
4+c= -8

c= -8-4 = -12
c= -12

b=2
c=-12