Question
1.4 The solutions of a quadratic equation are given by \( x=\frac{-2 \pm \sqrt{2 p+5}}{7} \) State the value(s) of \( p \) for which this equation will have: \( \begin{array}{ll}\text { 1.4.1 } & \text { Two equal solutions } \\ \text { 1.4.2 } & \text { No real solutions }\end{array} \)
Ask by Wyatt Little. in South Africa
Jan 27,2025
Real Tutor Solution
Tutor-Verified Answer
Answer
For the quadratic equation \( x = \frac{-2 \pm \sqrt{2p + 5}}{7} \):
1. **Two equal solutions:** When \( p = -\frac{5}{2} \)
2. **No real solutions:** When \( p < -\frac{5}{2} \)
Solution
To determine the values of \( p \) for which the given quadratic equation has two equal solutions or no real solutions, let's analyze the equation:
\[
x = \frac{-2 \pm \sqrt{2p + 5}}{7}
\]
### Understanding the Quadratic Equation
A general quadratic equation is given by:
\[
ax^2 + bx + c = 0
\]
The solutions (roots) of this equation are:
\[
x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
\]
Comparing this with the given equation:
\[
x = \frac{-2 \pm \sqrt{2p + 5}}{7}
\]
We can identify:
- \( 2a = 7 \) ⇒ \( a = \frac{7}{2} \)
- \( -b = -2 \) ⇒ \( b = 2 \)
- The discriminant \( D = 2p + 5 \) corresponds to \( b^2 - 4ac \).
### 1.4.1 Two Equal Solutions
Two equal (repeated) solutions occur when the discriminant is zero:
\[
D = 2p + 5 = 0
\]
Solving for \( p \):
\[
2p + 5 = 0 \\
2p = -5 \\
p = -\frac{5}{2}
\]
**Thus, the equation has two equal solutions when \( p = -\frac{5}{2} \).**
### 1.4.2 No Real Solutions
No real solutions occur when the discriminant is negative:
\[
D = 2p + 5 < 0
\]
Solving for \( p \):
\[
2p + 5 < 0 \\
2p < -5 \\
p < -\frac{5}{2}
\]
**Thus, the equation has no real solutions when \( p < -\frac{5}{2} \).**
### Summary
1. **Two equal solutions:** \( p = -\frac{5}{2} \)
2. **No real solutions:** \( p < -\frac{5}{2} \)
Answer:
1.4.1 Two equal solutions when p = –5⁄2;
1.4.2 No real solutions for all real numbers p with p < –5⁄2.
Reviewed and approved by the UpStudy tutoring team
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Mind Expander
For the quadratic equation to have two equal solutions, the expression under the square root, known as the discriminant, must equal zero. This means setting \( \sqrt{2p + 5} = 0 \), leading to \( 2p + 5 = 0 \). Solving this gives \( p = -\frac{5}{2} \). On the other hand, for the equation to have no real solutions, the discriminant must be negative. Thus, we want \( 2p + 5 < 0 \). This simplifies to \( p < -\frac{5}{2} \). So any value of \( p \) less than -2.5 will result in no real solutions.