Question

11. If A= x2–2x+16, B = 5x-3x2+ 3 and C= x2 + x + 9, find (a) A – 2B + 3C (b) A+ B-C (C) 2A - B + 2C​

Answer 1

Answer:

For equation x

2

+2x+3=0

Δ=2

2

−4(1)(3)=4−12=−8<0 so both roots are imaginary .

Hence, the roots are non-real. They will exist in complex conjugate pairs.

As one of the roots is common to ax

2

+bx+c=0 , the other root will also be the complex conjugate of it.

Hence, the roots of the two equations will be the same.

Since a, b, c∈R.

If one root is common, then both roots are common .

Hence,

1

a

=

2

b

=

3

c

a:b:c=1:2:3