Quadratic Root Cfb13B
1. The problem states: For the quadratic equation $$3.089\cdot 2x^1 - (1 - 3b)x + 5b = 0$$ one root is $b$. We need to find the value of $b$.
2. The general form of a quadratic equation is $$ax^2 + bx + c = 0$$ and if one root is known, say $r$, then it satisfies the equation: $$ar^2 + br + c = 0$$.
3. Here, the equation is $$3.089\cdot 2x - (1 - 3b)x + 5b = 0$$. Simplify the coefficient of $x$:
$$3.089 \times 2x = 6.178x$$
So the equation becomes:
$$6.178x - (1 - 3b)x + 5b = 0$$
4. Combine like terms for $x$:
$$6.178x - x + 3bx + 5b = 0$$
$$ (6.178 - 1 + 3b)x + 5b = 0$$
$$ (5.178 + 3b)x + 5b = 0$$
5. Since $b$ is a root, substitute $x = b$:
$$ (5.178 + 3b) b + 5b = 0$$
$$ 5.178b + 3b^2 + 5b = 0$$
6. Combine like terms:
$$3b^2 + (5.178 + 5) b = 0$$
$$3b^2 + 10.178b = 0$$
7. Factor out $b$:
$$b(3b + 10.178) = 0$$
8. Set each factor equal to zero:
- $b = 0$
- $3b + 10.178 = 0 \Rightarrow b = -\frac{10.178}{3} \approx -3.3927$
9. Check the options given:
A. -0.4; 0
B. -2.5; 0
C. 2.5; 0
D. 0
E. -0.8; 0
Only option D matches $b=0$ exactly.
Final answer: $b = 0$