Question

http://prntscr.com/8nj2ma

Answer 1

@hartnn

Answer 2

for the equation \(\Large ax^2+bx+c = 0\)
to have no real roots,
\(\large b^2 -4ac\)
must be less than 0.

so first compare x^2 +2x+c = 0 with ax^2 +bx+c = 0
and find a,b,c

Answer 3

a = 1, b = 2 c =1

Answer 4

a= 1, b = 2 and c = c


now find b^2 -4ac

Answer 5

2^2 - 4(1)(1) = 0

Answer 6

oh wait. c = c?

Answer 7

yes, keep c as c only

Answer 8

then it equals -4c+4?

Answer 9

\(\Large b^2-4ac < 0 \\ \large 4 - 4c < 0\)

factor out the 4

Answer 10

or just add 4c on both sides

Answer 11

4 < 4c

divide both sides by 4

Answer 12

4(1-c)?

Answer 13

yea, ok

4 (1-c) < 0

dividing both sides by 4

1-c < 0

or 1<c

Answer 14

which option satisfies that c>1 ??

Answer 15

there will be no real roots when c is greater than 1

Answer 16

so 0?

Answer 17

is 0 greater than 1 ?

Answer 18

3.

Answer 19

good!
\(\huge \checkmark \)

Answer 20

ty

Answer 21

welcome ^_^