1. Simplify:

$\frac{6-\sqrt{25}}{4}=$


  1. Use a calculator to estimate the value. Round to the nearest hundredth:

$\frac{-2-\sqrt{15}}{2} \approx$

Verified Answer :

  • Simplify the first expression: \(\frac{6-\sqrt{25}}{4} = \frac{6-5}{4} = \frac{1}{4} = \boxed{0.25}\).
  • Approximate the second expression: \(\frac{-2-\sqrt{15}}{2} \approx \frac{-2-3.87298}{2} \approx -2.93649 \approx \boxed{-2.94}\).

Explanation

  1. Understanding the Problem

The goal is to simplify the given expression \(\frac{6-\sqrt{25}}{4}\) and estimate the numerical value of \(\frac{-2-\sqrt{15}}{2}\) rounding to the nearest hundredth. We know that \(\sqrt{x}\) is the non-negative number whose square is \(x\). For the first part, we evaluate \(\sqrt{25}\), and for the second part, we use numerical estimation for the irrational value \(\sqrt{15}\).

  1. Simplifying the First Expression

To simplify \(\frac{6-\sqrt{25}}{4}\), we first evaluate the square root in the numerator: \(\sqrt{25} = 5\). Substituting this back into the expression gives \(\frac{6-5}{4}\). Performing the subtraction results in \(\frac{1}{4}\). Dividing 1 by 4, we get \(\frac{1}{4} = 0.25\).

  1. Estimating the Second Expression

To estimate \(\frac{-2-\sqrt{15}}{2}\), we first find the numerical value of \(\sqrt{15}\). Since \(3^2=9\) and \(4^2=16\), \(\sqrt{15}\) is between 3 and 4, specifically approximately \(3.87298\). Substituting this approximation into the expression, we get \(\frac{-2 - 3.87298}{2} = \frac{-5.87298}{2} = -2.93649\). Rounding to the nearest hundredth, the third decimal place (6) is 5 or greater, so we round up, resulting in \(-2.94\).

Examples

Understanding roots and numerical estimation is vital for fields like engineering or architecture where precise material measurements are necessary. For instance, if a structural beam's length is defined by an algebraic expression involving square roots, calculating its exact or approximate decimal value allows engineers to cut materials with the required accuracy. This logic underpins the precision of physical construction and design calculations.