Chapter 6: Problem 65
$$ \text { For Problems 51-80, solve each equation. (Objective 2) } $$ $$ 10 x^{2}-29 x+10=0 $$
Short Answer
Expert verified
The roots are \(x = 2.5\) and \(x = 0.4\).
Step by step solution
01
Understand the Problem
We are given a quadratic equation \(10x^2 - 29x + 10 = 0\) and need to find its roots. This is a standard quadratic of the form \(ax^2 + bx + c = 0\) where \(a = 10\), \(b = -29\), and \(c = 10\).
02
Use the Quadratic Formula
The roots of a quadratic equation \(ax^2 + bx + c = 0\) can be found using the quadratic formula: \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\). Substitute \(a = 10\), \(b = -29\), and \(c = 10\) into the formula.
03
Calculate the Discriminant
The discriminant \(\Delta\) is given by \(b^2 - 4ac\). Compute \((-29)^2 - 4 \times 10 \times 10 = 841 - 400 = 441\).
04
Solve for the Roots
Substitute \(\Delta = 441\) into the quadratic formula:\[x = \frac{-(-29) \pm \sqrt{441}}{2 \times 10} = \frac{29 \pm 21}{20}\]Calculate the two possible values for \(x\):1. \(x = \frac{29 + 21}{20} = \frac{50}{20} = 2.5\)2. \(x = \frac{29 - 21}{20} = \frac{8}{20} = 0.4\)
05
Solution Verification
Check both solutions by substituting them back into the original equation. For \(x = 2.5\):\[10(2.5)^2 - 29(2.5) + 10 = 62.5 - 72.5 + 10 = 0\]For \(x = 0.4\):\[10(0.4)^2 - 29(0.4) + 10 = 1.6 - 11.6 + 10 = 0\]Both solutions satisfy the equation, confirming their correctness.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Formula
The quadratic formula is a powerful tool used to find the roots of any quadratic equation of the form \(ax^2 + bx + c = 0\). The formula is expressed as:\[x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\]This formula helps solve for \(x\), the unknown variable in the equation. Here's how the formula works:
- The "\(-b \pm\)" part means that there are typically two solutions: one adds \(\sqrt{b^2 - 4ac}\) and the other subtracts it.
- \(b^2 - 4ac\) is a critical component known as the "discriminant," determining the nature of the roots.
- Divide by \(2a\) ensures that the solutions are correctly scaled according to the equation's leading coefficient \(a\).
Discriminant
The discriminant is a part of the quadratic formula found under the square root symbol \(b^2 - 4ac\). Its value tells us how many and what type of roots we can expect from the quadratic equation \(ax^2 + bx + c = 0\).
- If \(b^2 - 4ac > 0\), there are two distinct real roots. This occurs when the equation crosses the x-axis at two different points.
- If \(b^2 - 4ac = 0\), there is exactly one real root, also known as a repeated or double root. This means the parabola touches the x-axis at one point.
- If \(b^2 - 4ac < 0\), there are two complex roots, meaning the equation does not intersect the x-axis, and the solutions involve imaginary numbers.
Roots of Quadratic Equation
The "roots" of a quadratic equation are the values of \(x\) that satisfy \(ax^2 + bx + c = 0\). They are the solutions that make the equation true by reducing it to zero. In graphical terms, these roots correspond to the x-coordinates where the parabola representing the equation intersects the x-axis.To find the roots using the quadratic formula, substitute the values of the coefficients \(a\), \(b\), and \(c\) into the formula:\[x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\]In the problem you're tackling, the values are:
- \(a = 10\)
- \(b = -29\)
- \(c = 10\)
- When \(x = 2.5\), substitute into the equation and check if it equals zero.
- When \(x = 0.4\), do the same to ensure accuracy.