Question
Let $$a, b, c$$ be three real numbers such that $$2a + 3b + 6c = 0.$$ Then the quadratic equation $$a{x^2} + bx + c = 0$$ has
A.
imaginary roots
B.
at least one root in $$(0, 1)$$
C.
at least one root in $$(- 1, 0)$$
D.
both roots in $$(1, 2)$$
Answer :
at least one root in $$(0, 1)$$
Solution :
Take the equation $$2a{x^3} + 3b{x^2} + 6cx = 0.$$ Clearly, $$x = 0, 1$$ are two roots. Observe that $$a{x^2} + bx + c = 0$$ is the derived equation. So, one root lies between 0 and 1.