Question

a)y=x2-6x+8
b)y=-x2+6x+7
c)y=2x2+16x+30
d)y=-3x2+12x
e)y=x2-81
f) y=-10x2+5x

Answer 1

a) delta= 36-32
delta=4
x=6+/-2/2
x'= 6+2/2 = 4
x''= 6-2/2=2

b)
delta=36+28
delta=64
x=-6 +/-8/-2
x'= -6+8/-2 = -1
x''= -6-8/-2 = 7

delta= 256 -240
delta= 16
x= -6 +/-4/4
x'= -6+4/4= -1/2
x'= -6-4/4= -5/2

d)
delta= 144-0
delta= 144
x=-12 +/-12/-6
x'= -12+12/-6= 0
x''= -12-12/-6= 4

e)
delta= 0+324
delta= 324
x=0 +/-18/2
x'= 18/2 = 9
x''= -18/2 = -9

f)
delta= 25 +0
delta= 25
x=-5 +/-5 /-20
x'= -5+5/-20 = 0
x''= -5-5/-20 = -10/-20= 1/2