Quadratic EquationHard
Question
If the quadratic equation $ax^{2} - bx + 7 = 0$ does not have two distinct real roots, then the minimum value of $a + b$ is equal to :
Options
A.-8
B.-7
C.-6
D.-5
Solution
$f(x) = ax^{2} - bx + 7$
$$\begin{matrix} & f(0) = 7 \Rightarrow \ f(x) \geq 0\ \forall x \in R \\ & \ \therefore \end{matrix}$$
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