Lesson Example Discussion Quiz: Class Homework |
Step-3 |
Title: Quadratic equations with rational expression |
Grade: 1300-a Lesson: S2-L3 |
Explanation: Hello Students, time to practice and review the steps for the problem. |
Lesson Steps
Step | Type | Explanation | Answer |
---|---|---|---|
1 |
Problem |
Solve the equation: \$(2/x) + (3/(x^2)) = 5\$. |
|
2 |
Step |
The given equation |
\$(2/x) + (3/(x^2)) = 5\$ |
3 |
Step |
To solve this equation, let’s first make a substitution. Let’s set a variable, let’s say y, equal to \$x^(-1)\$. So, |
\$ y = 1/x \$ |
4 |
Step |
Now we can rewrite the equation in terms of y, rearranging the equation, we get: |
\$ 2y + 3y^2 = 5 \$ \$ 3y^2 + 2y - 5 = 0 \$ |
5 |
Formula: |
Now, we have a standard quadratic equation. We can solve it by factoring, completing the square, or using the quadratic formula |
\$ x = (-b ± \sqrt(b^2 - 4ac)) / (2a) \$ |
6 |
Hint |
In this case, a = 3, b = 2, and c = - 5. Plugging these values into the quadratic formula, we have: |
\$ y = (-2 ± sqrt(2^2 - 4 * 3 * -5)) / (2 * 3) \$ \$ y = (-2 ± 8) / 6 \$ |
7 |
Step |
So, we have two possible solutions for y then we get x value |
\$ y_1 = (8 - 2) / 6 = 6/6 = 1 \$ and \$ y_2 = (-8 - 2) / 6 = -10/6 = - 5/3 \$ \$ 1/x = 1 and 1/x = - 5/3 \$ \$ x_1 = 1/1 and x_2 = 1/(- 5/3) \$ \$ x_1 = and x_2 = - 3/5 \$ |
8 |
Step |
Therefore, the solutions to the original equation are \$ x_1 = 1 and x_2 = - 3/5 \$. |
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9 |
Choice.A |
This is the incorrect choice. The calculation showed that after rearranging and applying the quadratic formula, these values did not satisfy the equation |
\$ 1, - 5/3\$ |
10 |
Choice.B |
This choice is correct because after applying the quadratic formula or another method, these were the values of x that satisfied the original equation |
\$ 1, - 3/5\$ |
11 |
Choice.C |
Upon solving the equation, we find that x = −1 does not satisfy the given equation, making this option incorrect |
1, -1 |
12 |
Choice.D |
In this case, since option B correctly identifies the solutions, option D would not be the right choice |
None of these above |
13 |
Answer |
Option |
B |
14 |
Sumup |
Can you summarize what you’ve understood in the above steps? |
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