Question

5x^2-2x-3, 10x^2-5, -7x^2 +6x +9​

Answer 1

Step-by-step explanation:

As

3x

2

+6x+7

=

3(x+1)

2

+4

≥2,

and

5x

2

+10x+14

=

5(x+1)

2

+9

≥3

∴L.H.S.≥5 and always positive

Now

R.H.S.=4−2x−x

2

=5−(x+1)

2

≤5

∴ The equation holds only when, L.H.S.=R.H.S.=5

i.e.4−2x−x

2

=5

⇒x

2

+2x+1=0

⇒x=−1

Hence, only one solution to the above equation.

Was this answer helpful?